Meiosis is a special type of cell division, which occurs only in the germ cells during the process of development and maturation to form gametes. It consists of two successive cell divisions,
Meiosis 1 : First meiotic division, that reduces the NUMBER of chromosomes i.e. the parent cell is diploid(46 Chromosomes) and the daughter cells are haploid(23 Chromosome). It also causes genetic variation in the haploid by cross linkage.Meiosis 2 : Second meiotic division (Meiosis II) starts with two haploid parent cells and ends with four haploid daughter cells. Meiosis 2 like Meiosis 1, does not reduce the NUMBER OF CHROMOSOME that means the forming 4 daughter cells are haploid and their number of chromosome remains the same as the parent. BUT Haploid cells that go into the meiosis 2 have MORE AMOUNT OF CHROMOSOME THAN USUAL, thus MEIOSIS 2 REDUCES the amount of chromosome rather than the number of chromosome.The DNA of the primitive germs cells is replicated prior to the meiosis 1 only and there is no replication of DNA before Meiosis 2. The four final cells reulting from the two meiotic divisions are not only haploid(i.e. containing 23 chromosome) but they are also containing 1n amount of DNA so that when the gametes fuse together forming a zygote, both the amount and number of chromosome and DNA remains SAME.
_____________________________________[tex]\huge{\text{Why is Meiosis Important?}}[/tex]Meiosis is essential for the sexual reproduction of eukaryotic organisms because it enables genetic diversity through recombination, and the repair of genetic defects.
It contributes in genetic reassorment which ensures the genetic diversity in the offsprings. The genetic reassortment takes place by following two mechanisms:
During the prophase of meiosis 1, crossing over of genetic material between the homologous maternal and paternal chromosomes takes place which causes exchange of DNA fragments between the chromosome resulting is genetic diversity.During the anaphase of the first meiotic division, there is random distribution of maternal and paternal homologous chromosomes among the daughter cells which are produced as a result of meiotic division._____________________________________Best Regards,'Borz'which option shows the correct spelling of the word?
a. exhibit
b.exhibet
c.xibit
d.exibit
Answer:
A. exhibit
Explanation:
The only logical response!
Answer:
A
Explanation:
exhibit
which statement is not part of cell theory ?
Answer:
option (C) is your answer
I hope it's helps you
Answer:
C.
Explanation:
I am so sorry if I'm the wrong answer.
Identify and describe three mechanisms of movement of lymph through the lymphatic vessels.
Answer: Lymph fluid can only flow forward through lymphangions due to the closing of valves after fluid is pushed through by fluid accumulation, smooth muscle contraction, or skeletal muscle contraction if that makes sense. Without valves, the lymphatic system would be unable to function without a central pump.
Explanation:
2. Which object is part of climate
A river
B. bacteria
Coisture
Answer: I think it is B
Explanation:
What are the components of Darwin's theory of evolution?
(9 Points)
The evolution of a population happens slowly
Organisms have common ancestors
Organisms change over time
All of the above
Answer:
B
Explanation:
abcdefghijklmnopqrstuvwxyz
El numero de doploide de cromosomas de la especie humana que se restablece durante la
Answer:
El numero diploide de la especie humana se restablece durante la fecundación del ovulo por parte del espermatozoide, en donde estas dos células haploides (23 cromosomas) se unen formando un cigoto y próximamente un feto que poseerá los 46 cromosomas necesarios para la formación de un ser humano
Explanation:
What would happen to one of the organisms involved in a
symbiosis if the other organism is no longer present?
Answer:
Commensalism is a symbiotic relationship in which one species benefits while the other is not affected.
Explanation:
The organism of the ecosystem like the plants and the animals along with the microorganisms are connected and interlinked with one another through the ecological relationship. The relation could be positive, negative or neutral.
What is symbiotic relation?Symbiosis is an ecological relationship in which the organisms lives together and they both or a single organism is benefitted from the other.A symbiotic relationship in the ecosystem can be positive, neutral or negative and is of various types like commensalism, competition and parasitism.If the organism is removed from the symbiotic relationship then the factors like the shelter, food, locomotion etc. of the other organism can be affected adversely.Thus, symbiosis is important for the ecosystem.
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The notochord is an embryonic structure in humans that develops into
the spinal cord in the adult. What does the notochord suggest about
humans' relatedness to other species?
M
Answer:
In anatomy, the notochord is a flexible rod formed of a material similar to cartilage. If a species has a notochord at any stage of its life cycle, it is, by definition, a chordate. The notochord lies along the anteroposterior ("front to back") axis, is usually closer to the dorsal than the ventral surface of the animal, and is composed of cells derived from the mesoderm.
A student collected the animal shown below on field trip. The student used a dichotomous key and a microscope to classify the animal.
How should this animal be classified?
A. Arthropoda
B. Annelida
C.Mollusca
D. Platyhelminthes
Answer: The answer is D: Platyhelminthes
Explanation: took the test and it came back
Circle the letter of each sentence that is true about the cell wall.
a. Cell walls are made of cellulose.
b. Plant cells have cell walls.
c. Animal cells have cell walls.
d. Water and oxygen cannot pass through the cell wall
Answer:
D.Water and oxygen cannot pass through the cell wall
Explanation:
not sure
what allows the blood to clot
what not to do when handling acids and bases
Wear protective gear (goggles, long-sleeved clothes, and gloves) when using acids and bases. Do not allow acids or bases to come in contact with skin or eyes. Limit the amount of acids and bases transported for usage around the house. Cap the bottles of acid and base cleaners tightly.
Main features of Solar System, Main facts of solar system
Answer:
The main features of the solar system:
The Sun is our nearest star.
The planets orbit the Sun.
The time taken to orbit the Sun increases with distance from the Sun.
Gravity keeps the planets in orbit around the Sun and the moons in orbit around their planets.
From the Sun, the order of the planets is Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. You might need to be able to recall this in the exam.
The planets go around the Sun in slightly squashed circular elliptical orbits.
Pluto is classified as a dwarf planet or planetoid. It has a highly elliptical or eccentric orbit.
Main facts
The definition of a planet and a moon is fuzzy. ...
Comets and asteroids are leftovers. ...
The planets are all on the same “plane” and orbit in the same direction. ...
We're nowhere near the center of the galaxy. ...
But the Solar System is bigger than you think. ...
The Sun is hugely massive. ...
Explanation: (:
At what age does a person begin to think about education and career goals over
relationship with friends?
Ten
Fourteen
Eighteen
Late twenties
Answer:
Somewhere in the Fourteen-ish and Eighteen-ish, that's just my opinion of this matter.
Eighteen is the perfect age does a person to begin to think about education and career goals over relationships with friends.
What does adulthood teach us?Being an adult means being responsible for yourself. So instead of doing everything you want to do, you start to compromise. You learned that you need to take care of your problems instead of running away from them. Instead of pulling out an all-nighter, you learn to manage your time better.
After the eighteenth of a person, a person should be considered an adult. Adulthood is a stage where a person considers themselves more responsible for their lives and carrier goals.
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The world's atmosphere can hold more moisture as it warms. As a result, the overall number of heavy storms has likely increased since midcentury due to global warming. True or false?
Answer:
True.
Explanation:
Yes, the number of heavy storms has increased due to global warming because of the holding power of moisture by the atmosphere due to higher temperature. When the air is warmed, the air can hold more water at that temperature so due to more holding power of moisture by the air the number of storms increases. One NASA study supports that global warming is causing the increase in number of extreme storms especially in the tropical ocean.
What would happen in an ecosystem without decomposers? (3 points)
Answer:
Without decomposers, dead leaves, dead insects, and dead animals would pile up everywhere. And most importantly decomposes make vital nutrients available to an ecosystem primary producers- usually plants and algae.
The picture below shows some features of the ocean floor. (1 point)
At which of these locations does the ocean floor spread apart to form new oceanic crusts?
Location A
Location B
Location C
Location D
Answer:
At D
it spreads at the mid ocean ridge ig
What role does the process of photosynthesis play in cycling materials and energy through the ecosystem
Answer: Photosynthesis has a role in the cycling of matter and flow of energy into and out of organisms.
Explanation:
The flow of energy and cycling of matter can be traced. The chemical reaction by which plants produce complex food molecules to occur requires an energy input
What process do animals go through in molecular energy is available?
it says it all sorry
describe properties of minerals.
please help!
Factors that include precipitation, temperature, climate, sunlight are all examples of _______ factors
A) biotic
B)abiotic
C)biological
D)ecological
Answer: the answer is b, abiotic
Explanation: Abiotic factors are the non-living parts of the environment that can often have a major influence on living organisms and Abiotic factors include water, sunlight, oxygen, soil and temperature.
Answer: D
Explanation:
What can the reader conclude about ecosystems based on the information in this passage?Ecosystems Ecosystems are are always always distinctly distinctly different different and and unique.unique.Ecosystems Ecosystems are are interrelated interrelated with with other other ecosystems ecosystems surrounding surrounding or or including including them.them.Ecosystems Ecosystems are are slow-slow-developing developing entities entities of of biological biological communitiesmunities.Ecosystems Ecosystems are are clusters clusters of of communal communal habitats habitats in in an an area.area.
um what are the anwsers for the question
As a runner begins to run a race, his or her respiration rate will increase. The runner begins to breathe deeper and at a rapid rate. In addition, the heart beats more quickly. This will result in more oxygen and nutrients delivered to the muscle cells. Which three body systems are working together to help out the muscle cells?
Answer:
respiratory system
circulatory system
digestive system
when a dead animal is burried how long does it take to decompose and form bones? please answer though its awkward me asking this and be sincere ....il give you brainliest no links please
Answer:
It takes millions of years.
Explanation:
As when a dead animal is buried it should reach sedimentary rock
1. How many layers are there in an arthropod's exoskeleton? What is the main function of
each layer?
Explanation:
The exoskeleton and molting
The success of arthropods derives in large part from the evolution of their unique, nonliving, organic, jointed exoskeleton (see figure), which not only functions in support but also provides protection and, with the muscle system, contributes to efficient locomotion. The exoskeleton is composed of a thin, outer protein layer, the epicuticle, and a thick, inner, chitin–protein layer, the procuticle. In most terrestrial arthropods, such as insects and spiders, the epicuticle contains waxes that aid in reducing evaporative water loss. The procuticle consists of an outer exocuticle and an inner endocuticle. In the exocuticle there is cross-bonding of the chitin–protein chains (tanning), which provides additional strength to the skeletal material. The hardness of various parts of the exoskeleton in different arthropods is related to the thickness and degree of tanning of the exocuticle. In crustaceans, additional rigidity is achieved by having the exoskeleton impregnated with varying amounts of calcium carbonate.
arthropod integument
arthropod integument
Diagrammatic section through the arthropod integument.
Encyclopædia Britannica, Inc.
The formation of an exoskeleton required the simultaneous solution of two functional problems in the evolution of arthropods: If the animal is encased in a rigid covering, how can it grow and how can it move? The problem of growth is solved in arthropods by molting, or ecdysis, the periodic shedding of the old exoskeleton. The underlying cells release enzymes that digest the base of the old exoskeleton (much of the endocuticle) and then secrete a new exoskeleton beneath the old one. At the time of actual shedding, the old skeleton splits along specific lines characteristic of the group, and the animal pulls out of the old skeleton as from a suit of clothes. The old skeleton is usually abandoned but in some species is eaten. The new exoskeleton, which is soft and flexible, is then stretched by localized, elevated blood pressure augmented by the intake of water or air. Hardening occurs by stretching and especially by tanning within a number of hours of molting. In crustaceans, calcium carbonate is deposited into the new procuticle. (Soft-shell crabs are simply newly molted crabs.) Additional endocuticle may be added to the exoskeleton for some days or weeks following molting.
molting
molting
Grasshopper shedding its exoskeleton.
© Cathy Keifer/Dreamstime.com
Molting is under hormonal control, and there is a long preparatory phase that precedes the process. The steroid hormone ecdysone, secreted by specific endocrine centres and circulated in the blood, is the direct initiator of molting. The actual timing of a molt, however, is regulated by other hormones and commonly by environmental factors. The interval between molts is called an instar. Because of the frequency of molts, instars are short early in life but grow longer with increasing age. Some arthropods, such as most spiders and insects, stop molting when they reach sexual maturity; others, like lobsters and crabs, molt throughout their lives. Most of the larger spiders of temperate regions, for example, molt about 10 times before reaching sexual maturity. As a result of molting, the length and volume of an arthropod display steplike increases over the life span, but internal tissue growth is continual as in other animals.
Loss of a limb is a common hazard in the life of many arthropods. Indeed, some arthropods, such as crabs, are capable of amputating an appendage if it is seized by a predator. The limb is then regenerated from a small, nipplelike rudiment formed at the site of the lost limb. The new limb develops beneath the old exoskeleton during the premolt period and then appears when the animal molts.
Answer:
Three layers
Explanation:
Outer= Composed of proteins and lipids. Repels water and prevents desiccation in terrestrial places.
Middler=Provides primary protection
Inner=Flexibke at joints, muscles attach here.
If there is a piece of metal will it still be attracted to the magnetic even if it is outside of the magnetic field? Will the magnetic field line connect to the object?
Answer:
It will still attract.
Explanation:
When you think of it, when some of us were little we used magnets and played with them and would do a "magic" trick. We would put a magnet underneath the table and one on top and move the one underneath which would move the one on top without us touching it.
Hope this helps!!
The molecule that carries a great deal of chemical energy in its chemical bonds and is made in both photosynthesis and cellular respiration is
DNA
RNA
NADPH
ATP
Glucose
Land from which water runs off into streams is known as a
Answer:
Run-off
Explanation:
Water from land slides into streams and ponds are called run-off.
In the disease myasthenia gravis, the human body makes-by mistake- antibodies to its own acetylcholine receptor molecules. These antibodies bind to and inactivate acetylcholine receptors on the plasma membrane of muscle cells. The disease leads to devastating progressive weakening of the muscles of people affected. Early on, they may have difficulty opening their eyelids, for example, and, in an animal model of the disease, rabbits have difficulty holding their ears up. As the disease progresses, most muscles weaken, and people with myasthenia gravis have difficulty speaking and swallowing. Eventually, impaired breathing can cause death. Explain which step of muscle function is affected
Answer:
Muscle contraction function.
Explanation:
The nerve endings possess synaptic acetylcholine vesicles ready to be released. The action potential depolarizes the presynaptic terminal and increases the concentration of axoplasmic calcium; Acetylcholine molecules are thus released, so that the concentration of the neurotransmitter at postsynaptic (nicotinic) receptors is temporarily increased. This is followed by post-synaptic membrane depolarization, muscle membrane action potential with increased rnioplasmic calcium concentration, and finally muscle contraction. Acetylcholine is hydrolyzed by acetylcholinesterase and resynaptic at the presynaptic level by cholinecetyltransferase. The etiopathogenesis of myasthenia gravis is autoimmune and there are antibodies against acetylcholine receptors that circulate in the blood, as well as a decrease in the number of receptors on the motor plates, that is, it is produced by the postsynaptic blockage of the myoneural plaque, that generates fatigue and localized or generalized muscle weakness that is characterized by the worsening of the contractile force of the muscle.
An easy 10 points
Make up your own scientific theory.
Answer:
Ammmmm theory focused on the structuralist or central-peripheral paradigm, the analysis of internal colonialism and marginality, and studies on dependence are discussed here. Wherever they come, the divergent key positions of the Latin American school are important.