The population in South Africa is more prone to sickle cell anemia (genotype "ss"). People with genotype "ss" survive only up to 14-15 years of age. People with "SS" are prone to malaria because the parasite resides inside their RBCs. People with genotype "Ss" are resistant to malaria because the parasite cannot reside inside their RBCs, and they can live a normal life (without sickle cell anemia).What kind of evolutionary force must be operative in South Africa?
A.
Stabilizing selection
B.
Directional selection
C.
Disruptive selection
Answer:
(a) stabilizing selection
Explanation:
Sickle-cell anaemia is a recessive disorder caused by the presence of two recessive alleles "s", so the genotype is "ss". This disorder is characterized by sickle haemoglobin. In an area with malaria, heterozygous individuals "Ss" (with one dominant allele and one recessive allele) have an advantage. These individuals will have both normal and sickle haemoglobin. But pathogen that causes malaria affects only normal haemoglobin, so heterozygous individuals will have half of the haemoglobin resistant to the pathogen and those individuals are resistant to malaria.
Stabilizing selection favours heterozygotes Ss, disruptive selection favours dominant (SS) and recessive (ss) homozygotes, while directional selection favours dominant (SS) or recessive (ss) homozygotes. Since in this example, people with genotype Ss (heterozygotes) are at an advantage, then this is an example of stabilizing selection.
hope this helps:)
Name the cavity between the nose and mouth.
A. pharynx
B. larynx
C. trachea
D. Esophagus
The cavity which separate or in between the nose and the mouth is the nasal cavity.
The nose and the mouth meet at a junction called the pharnx; option A
What is nasal cavity?The nasal cavity refers to a large, air-filled space above and behind the nose in the middle of the face. It is the cavity which divides the nose and mouth.
However, the nasal septum divides the cavity into two cavities .
The larynx is the passageway for air between the pharynx above and the trachea below.The pharynx carries air, food and fluid down from the nose and mouth.So therefore, the cavity which separate or in between the nose and the mouth is the nasal cavity.
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PLEASE HELP!!!!! 40 pts!!!
Besides water, which of the following compounds are found most in sea water?
sodium bromide
sodium chloride
hydrogen chloride
magnesium chloride
Answer:
Sodium Chloride :>
Explanation:
⠀⠀Beside water Sodium Chloride ( NaCl ) is found most in seawater .
More Information :
Sodium constitutes of 1.94 % of all the constituents ,Followed by the Chloride which constitutes of 1.08% .Minerals like Potassium (K) , Iodine (I) , Magnesium are also found in seawater .Explain how our body systems work together to get oxygen into and around our body.
An antibiotic is a type of medication that cures infectious diseases. Why does the word antibiotic suggest that these
medications would be ineffective against viruses?
Explanation:
Antibiotics cannot kill viruses because bacteria and viruses have different mechanisms and machinery to survive and replicate. The antibiotic has no “target” to attack in a virus. However, antiviral medications and vaccines are specific for viruses.
Which statement accurately describes how the understanding of the Doppler effect is applied to the study of galaxies?
Which of the following is NOT a feature found
in nematodes?
A. complex nervous system
B. bilateral symmetry
C. fluid-filled body cavity
D. digestive tract with two openings
Complex nervous system is not a feature found in nematodes and is denoted as option A.
What are Nematodes?
They are also referred to as roundworm and have unsegmented thread-like body with a distinct mouth and anus.
They have a simple nervous system which runs along the length and width of the organism.
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Explain what happens to the level of the sucrose solution in the glass tube
The level of sucrose solution will rise in the glass tube because water molecules will pass through the semipermeable membrane into the tube as water potential is higher outside than inside the tube.
What is osmosis?Osmosis is the movement of water molecules from a region of low solute concentration or high water potential to a region of high solute concentration or low water potential through a semipermeable membrane until equilibrium concentration is attained.
The movement of water molecules is based on a concentration gradient, from a region where there are more water molecules to a region where there are fewer water molecules.
Thus, this could be the answer.
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Many cities are working to reduce waste by finding new uses for garbage.
which action could help a city reduce landfill waste?
a. providing discarded building supplies to residents
b. building new incinerators
c. providing plastic trash bags to residents
d. downsizing recycling facilities
Building new incinerators is an action which could help a city reduce landfill waste and is denoted as option B.
What is Incineration?This is a method used to treat and involves burning the wastes in special structures referred to as incinerators.
Incineration and recycling are the main methods which help reduce landfill waste.
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18. Brayden is trying to figure out how petal shape is determined in two different roses. In the pink rose, the copies of the gene are the same as each other. In the yellow rose, the copies of the gene are different from each other. How does this affect how many types of proteins there are in each petal cell?
The pink rose has a type of protein for the petal shape on the other hand, the yellow rose has two types of protein for the petal shape feature.
What is the relation of protein with plant characteristics?Plant proteins also like other proteins, provide a variety of enzymatic, structural, and functional functions.
They also serve as storage media to suit the nutritional and development requirements of growing seedlings.
These can also responsible for coloration in plants.
Thus, as in the given scenario, the pink rose has a type of protein for the petal shape on the other hand, the yellow rose has two types of protein for the petal shape feature.
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Along with insulin, amylin is a hormone that a diabetic pancreas fails to produce. It is comprised of a long chain of amino acids. It cannot cross the cell membrane, so it binds to a receptor on the cell surface to elicit an action. Which hormone class is amylin
Options:
A prostaglandin
B protein hormone
C. peptide hormone
D. steroid hormone
Answer:
Amylin is peptidal harmone. Thus, the correct option is C.
What is hormone?Hormones are the chemical messengers of the body. They make their way through your bloodstream to tissues and organs. They have a long-term effect on a variety of processes, including growth and development.
Amylin is a peptide hormone produced in tandem with insulin by the pancreatic -cell and is hence lacking in diabetics. It works as a satiety agent by inhibiting glucagon secretion and delaying stomach emptying. As a result, amylin replacement could potentially improve glycemic control in some diabetics.
Amylin is a 37-amino-acid peptide hormone released by pancreatic beta-cells in response to a food stimulation together with insulin. It is inadequate in Type 1 diabetes patients and increased in Type 2 diabetes patients in the early stages, a disease marked by hyperinsulinemia.
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Please help ASAP
Write the characteristics in which porifera differ from the characteristics of animal kingdom?
Answer:
see the file attached!!
Photosynthesis is an integral part of what cycle?
Answer:
photosynthesis is a part of the global carbon cycle
Mountain ranges form along ___ plate boundaries via orogenic processes.
Rift valleys formed through the stretching of divergent plates occurs through a/an ___ process.
The formation of mountain ranges occurs as a result of ___.
Scientists observe an extremely long ___ area in a continental plate during an orogenic process.
___ processes cause vertical plate motion along tectonic plates.
1. Mountain ranges form along convergent plate boundaries via orogenic processes.
What is tectonic plates?The formation of mountains is caused by tectonic plates. A mountain is formed when two tectonic plates move towards each other and collide, resulting in altitudes that can take years to reach but that eventually create massive mountains through what are known as convergent plate borders.
2. Rift valleys formed through the stretching of divergent plates occurs through a divergent boundary process.
When tectonic plates separate, they can leave low ground areas like the Rift Valley, which are produced by diverging continental plate borders. They can be found on the surface of the Earth or at the bottom of the ocean, and they are formed by the expansion of the seabed.
3. The formation of mountain ranges occurs as a result of orogeny.
This process occurs when one continental plate dips and the other rises, allowing mountain ranges to form. Orogeny is the name given to this process.
4. Scientists observe an extremely long deformation area in a continental plate during an orogenic process..
Scientists use tectonic plate simulations to study this deformation in order to better predict natural disasters such as earthquakes.
5. Epeirogenic process causes vertical plate motion along tectonic plates.
The vertical movement of a continent that generates soft arcs or rises parts uniformly is known as epeirogeny.
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List the cups in order of the most hatched eggs to the least
Acid rain is liquid deposition that occurs when sulfuric and nitric acids get dissolved in rainwater and reach the ground affecting the whole ecosystem.
What is acid rain?
Acid rain refers to the liquid deposition of water drops charged with dissolved pollutive acids, like sulfuric and nitric acids.
Liquid deposition can be caused by rains (acid rain), snow, dew, or fog. During this event pollutive acids are dissolved in atmospheric water drops and are driven to the ground.
Usually, rainwater pH is about 5.6.
However, with high concentrations of acids in the environment, rainwater pH decreases.
When the the rain gets to the ground, they produce a series of chemical changes that alter the natural pH of the soil and water and have a consequent effect on ecosystems.
Day 1
Cup pH
F 8
E 7
D 6
C 5
B 4
A 3
Day 2
Cup pH
D 6
E 7
F 8
C 5
B 4
A 3
Day 3
Cup pH
E 7
D 6
F 8
C 5
B 4
A 3
Day 4
Cup pH
E 7
D 6
F 8
C 5
B 4
A 3
According to this data, we can assume that eggs need a neutral to basic pH to hatch. Acid media notoriously affects egg hatching.
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Which of the following requires the least amount of energy to produce?
Question 15 options:
vegetables
chickens
canned soda
cattle
Answer:
An astronaut who weighed 150 pounds on Earth found that his weight on Jupiter was 400 pounds. He captured an alien that weighed 120 pounds on Jupiter. What is the alien's weight on Earth?
Explanation:
a.
45 pounds
c.
500 pounds
b.
30 pounds
d.
320 pounds
Organisms that have catalase
what are you looking for in your observations when you are looking for evidence of a reaction?
does the plant tissue that was tested contain catalase?
does the animal tissue that was tested contain catalase?
Higher vascular plants contain catalase to metabolize Hydrogen peroxide (H2O2) in mitochondria and chloroplasts.
What is catalase?Catalase is a key enzyme used by organisms to metabolize Hydrogen peroxide (H2O2), which is a reactive substance.
The animal tissues also contain catalase which they use to generate H2O and thus remove toxic H2O2.
In conclusion, higher vascular plants contain catalase to metabolize Hydrogen peroxide (H2O2) in mitochondria and chloroplasts
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Why is a theory a hypothesis?
Answer:
Because a theory is a speculation on a topic that is in short words, the point of view on a group or individual. A hypothesis is an educated guess on a topic, which is relatable to a theory, since they are both considered, "thinking" or, "speculations" about one thing at a given time.
explain mixed cropping
Answer:
Mixed cropping is also known as inter-cropping, polyculture, or co-cultivation. It is a type of agriculture that requires planting two or more plants simultaneously in the same field, interdigitating the plants so that they grow together.
Typically a mix of legumes and cereals or tuber crops is a common practice in marginal agro-ecological environments. The mixtures can be flexibly arranged to conditions such as late or early onset of the rainy season or status of soil fertility in different fields.
genetic drift simulation:
Why did you have to "restock" your bag between generations? How does this relate to genotypes and inheritance?
Why are fats a better source of energy than carbohydrates on a per carbon basis?.
Fats and carbohydrates are the macromolecules that are energy sources. Fats are a better source of energy than carbohydrates as three fatty acid molecules have energy equivalent to 16 carbons.
What are fats?Fats are the energy-providing macromolecule and are stored in the adipose tissue. They are made of fatty acids that are the source of the energy.
Fats contain the triglyceride molecule that produces fatty acids that produce the equivalent energy as the sixteen carbon molecules and hence are a more efficient source.
Therefore, fats are a better source of energy.
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Darwin saw populations of various species that seemed well-suited to their environment. What did this suggest?
Answer:
Species adapte to their environment over time.
briefly discuss five economic importance of microorganisms
Answer:
Bacteria are economically important as these microorganisms are used by humans for many purposes. The beneficial uses of bacteria include the production of traditional foods such as fudge, yogurt, cheese, and vinegar. Microbes are also important in agriculture for compost and fertilizer production.
Answer:
The human body has 10 microorganisms for every human cell, and these microbes contribute to digestion, produce vitamin K, promote the development of the immune system, and detoxify harmful chemicals. They are also important in agriculture for compost and fertilizer production.
Explanation:
How does excess calcium from dissolved bones affect kidney function?
group of answer choices
excess calcium travels around the bloodstream until it reaches the kidneys, where it accumulates and causes kidney failure.
excess calcium travels around the bloodstream until it reaches the kidneys, where it is dissolved and increases kidney function.
excess calcium travels around the bloodstream until it reaches the kidneys, where it is dissolved and narrows kidney blood vessels.
excess calcium travels around the bloodstream until it reaches the kidneys, where it accumulates and can form kidney stones.
Answer:
The last choice
Explanation:
Hypercalcemia is a condition in which the calcium level in your blood is above normal. Too much calcium in your blood can weaken your bones, create kidney stones, and interfere with how your heart and brain work.
i’m stuck please help it’s due and grades are closing
Answer please quick
Answer:
animal respiration release, fossil fuel burning release, photosynthesis remove
Explanation:
also please don't cheat on an active mapnwea test. I'm going to assume this is a question from after you took the test, and you just want to confirm (so that I can answer it without feeling bad)
(if this is directly during a test I'm fairly certain it's against the rules anyway)
. circle the letter of each sentence that is true about the light-dependent
reactions. correct the false statements.
a. they convert adp into atp.
b. they produce oxygen gas.
c. they convert oxygen into carbon dioxide.
d. they convert nadp+ into nadph.
e. photosynthesis begins when pigments in photosystem i absorb light
Light-dependent reactions are the electron flow along the electron transporter chain. The final products are NADPH and ATP production and Oxygene release.
What are the light dependent reactions?
Light-independent reactions occur in the thylakoyd membrane where pigments are placed. They involve light absorption and the electron flow from water to NADPH.
During light-dependent reactions, oxygen is released, while ATP and NADPH are produced. Both of them are used during light-independent reactions.
Energy is released as electrons move through the chain. This energy pumps H+ into the thylakoid compartment, and then they power the formation of ATP as they flow back out.
Steps,
1. Luminous energy is trapped by chlorophyll in Photosystem II.
2. When the pigment molecules absorb light, electrons provided by water molecules get in a higher energy level.
3. The excited electrons go through the electron transport chain from Photosystem II to a less energetic level in photosystem I.
4. When the excited electrons leave photosystem II, they are replaced by new electrons extracted from the water molecules.
5. Luminous energy absorbed move the electrons from the photosystem I to another electron acceptor, from where they get transported again and used to produce NADPH molecules.
6. When electrons leave Photosystem I, they are replaced by new electrons coming from photosystem II.
7. When the water molecule breaks down, hydrogen ions remain in the thylakoid lumen, from where they are pumped to the stroma by the ATP synthase.
8. The released energy is used to produce ATP molecules.
9. Hydrogen ions go back from the stroma to the thylakoid compartment.
a. they convert adp into atp ⇒ true, using energy from H+ pump.
b. they produce oxygen gas ⇒ true, they release oxygen when water molecule breacks
c. they convert oxygen into carbon dioxide ⇒ false, CO₂ is not involved in light-dependent reactions.
d. they convert nadp+ into nadph ⇒ true, they reduce NADP+ into NADPH using H+
e. photosynthesis begins when pigments in photosystem i absorb light ⇒ false, photosynthesis begins when pigments in photosystem II absorb light.
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How many moles of hydrogen gas what contains 2.4 x 1024 hydrogen atoms
9. What part of the body covers the windpipe when you swallow?
O tongue
O epiglottis
O bronchi
O diaphragm
Answer:
epiglottis
Hope it helps:)
Answer:
B. epiglottis
Explanation:
this is the part of your body that covers the windpipe when you swallow.
What are the 5 elements of digestion
The five elements of digestion are:-
1. Ingestion:- Taking food into the mouth.
2. Digestion:- Breaking down of food so it can be absorbed into the small intestine.
3. Absorption:- Food passes into blood system from small intestine.
4. Assimilation:- The way in which the body uses food.
Getting rid.
5. Getting rid of undigested and unabsorbed food.
What is digestion?
Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma.
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