In 1956 Tijo and Levan first successfully counted human chromosomes. The reason it would have taken so manyyears to have done so would have included all but which of the following?

a. Watson and Crick's structure of DNA was not done until 1953.
b. Chromosomes were piled up on top of one another in the nucleus.
c. Chromosomes were not distinguishable during interphase.
d. A method had not yet been devised to halt mitosis at metaphase.

Answers

Answer 1

Answer:

A

Explanation:

The correct answer would be that Watson and Crick's structure of DNA was not done until 1953.

The fact that chromosomes are condensed together in the nucleus, are not distinguishable during interphase, and a method had not yet been devised to halt mitosis at metaphase could have plausibly delayed the successful counting of human chromosomes.

On the other hand, the discovery of the structure of the DNA could not have delayed the study of chromosomes because the DNA structure has no bearing on the karyotyping of chromosomes.

The chromosomes of organisms are best studied using a relevant microscope during metaphase when they would have fully decondensed and align at the equator of the cell or the metaphase plate. At the interphase phase of the cell cycle, chromosomes are full condensed under the view of the microscope.

The correct option is, therefore, A.


Related Questions

Why are the digestive systems of birds, ruminants and humans different?

Answers

Answer:

Humans and many other animals have monogastric digestive systems with a single-chambered stomach. Birds have evolved a digestive system that includes a gizzard where the food is crushed into smaller pieces.

Explanation:

Answer:

The digestion process in Ruminants is completely different from humans.

This is because the digestion process in Ruminants begins by chewing and swallowing its food. The main diet for these animals includes grass, leaves and other parts of plants.

4. How does temperature affect chemical weathering?
A. It is an agent of weathering.
B. It affects the amount of oxygen involved in weathering.
C. It affects the rate of weathering.
D. It affects the type of weathering.

Answers

Answer:

C.

Explanation:

It affects the rate of weathering.

Long-term activation by nuclear receptors differs from the more transient membrane receptor signaling for what reason

Answers

i have no idea but i think because long term activation is long term rather than nuclear. this is wrong


6. In general, as both the force and velocity of impact increase, what happens to the diameter of
the resulting blood droplets?

Answers

Answer: depending on viscosity, mass and velocity of impact, if droplet integrity is maintained, as velocity increases, diameter will increase from

Approximately d*sqrt(2) to 2*sqrt(d^3/6a) where d is original diameter and a is thickness when the droplet flattens into a disc.

Explanation:

This applies generally to any liquid droplet, which by inference falls and impacts a solid surface. The impact force is mgh where m= mass, g= acceleration due to gravity, h= initial height.

A liquid droplet deforms on impact. Assume the drop is sperical, then the deformation distance, d= diameter of the droplet then the average impact force = mgh/d.

The droplet may spread, splash or bounce, depending on viscosity and force, which depends on mass and velocity immediately before impact.

All than can be said is that if the droplet maintains integrity it could achieve the shape of half a highly flattened oblate spheroid. Approximating this with a flattened disc of thickness a, and an original volume of 4/3pi(d/2)^3, the volume as a disc =a*pi*r^2 so the horizontal diameter = 2*sqrt(d^3/6a)

It is not really possible from the available data to determine whether the droplet would remain its integrity, but at sufficiently low force/velocity, the droplet could retain a near-hemispherical shape, giving a horizontal diameter of the hemisphere = d*sqrt(2)

As velocity increases, if integrity is maintained, the diameter will increase from the second approximation to the first

Natural selection may affect allele frequency in populations due to the fundamental forces of evolution except which of the
following?
O gene drive
O gene flow
O genetic drift
O mutation

Answers

Answer:

gene flow.

Explanation:

its right I think

Geologists describe rocks by observing mineral composition and color, texture, and ______.

Answers

Answer:

I believe surface

Explanation:

Desert plants and animals are adapted to the lack of what and high

Answers

The two main adaptations that desert animals must make are how to deal with lack of water and how to deal with extremes in temperature. Many desert animals avoid the heat of the desert by simply staying out of it as much as possible

Answer:

lack of water and high concentration of heat and dryness

Explanation:

Deserts don't get that much rainfall, so desert wildlife are adapted to survive in such a dry climate. Take the camel, for instance, it can store three bathtubs of water in it's hump, so it can go a very long time without water. And without that rainfall, the desert is dry and, usually, very hot. Animals have adapted to this by only coming out in the nighttime when it's cooler.

hope this helped:)

Which type of wave forms at the boundary between air and water in the open

ocean?


A. Surface

B. Longitudinal

C. Electromagnetic

D. Transverse

Answers

Answer:surface

Explanation:

Just believe me miss gorl

Answer:

surface waves form at the boundary where air and water meet in open ocean.

Explanation:

Just did the quiz.

Which type of cell are found in the leaves of a tree?
O eukaryotic animal
O chloroplastic
O prokaryotic
O eukaryotic plant

Answers

Answer:

Palisade parenchyma cells

Explanation:

Palisade parenchyma cells are elogated cells located in many leaves just below the epidermal tissue. Spongy mesophyll cells occur below the one or two layers of palisade cells. Ray parenchyma cells occur in wood rays, the structures that transport materials laterally within a woody stem.

Answer:

eukaryotic plant

Explanation:Unit 2 Test: Cells

What is and example of an molecule
Muscle tissue
Protein
Stomach
Unicellular organism

Answers

An example of an molecule is Protein

Summarize how dead organisms become oil or natural gas (2-3 sentences)

Please do this for me? I will give brainliest when it pops up if you help me! x thx

Answers

Answer:

Petroleum, also called crude oil, is a fossil fuel. Like coal and natural gas, petroleum was formed from the remains of ancient marine organisms, such as plants, algae, and bacteria. ... Millions of years ago, algae and plants lived in shallow seas

what animal kingdoms were divided

Answers

Answer:

The scheme most often used currently divides all living organisms into five kingdoms: Monera (bacteria), Protista, Fungi, Plantae, and Animalia. This coexisted with a scheme dividing life into two main divisions: the Prokaryotae (bacteria, etc.) and the Eukaryotae (animals, plants, fungi, and protists).

A patient with chronic venous insufficiency comes to the doctor's office complaining of leg pain. The physician prescribes two thigh-length gradient compression stockings, 45 mmHg each. HCPCS code(s):______-

Answers

Answer:

What class is this?

Explanation:

(Also if you look it up on gooogle there is an answer.) cannot answer this for you though.

The correct HCPCS Level II codes for two below the knee gradient compression stockings, 18-30 mmHg each, are A6530 x 2.

The HCPCS Level II code A6530 is used to report gradient compression stockings, below knee, 18-30 mmHg, each. The code is divided into two parts: the first part identifies the type of stocking (gradient compression), and the second part identifies the location of the stocking (below knee). The mmHg value indicates the level of compression.

In this case, the patient was prescribed two below the knee gradient compression stockings, 18-30 mmHg each. This means that the physician ordered two stockings, each of which is designed to provide a compression level of 18-30 mmHg.

The correct HCPCS Level II code for this prescription is A6530 x 2. The "x 2" indicates that two stockings are being ordered.

To learn more about chronic venous insufficiency, here

https://brainly.com/question/31838050

#SPJ2

The complete question is:

A patient with chronic venous insufficiency came to the doctor’s office with complaints of bilateral leg pain. The physician prescribed two below the knee gradient compression stockings, 18-30 mmHg each. Assign the correct HCPCS Level II codes.

How does gradualism explain the evolution of different species?

New species appear as a result of small changes over a long period of time

New species appear as a result of small changes over a short period of time

New species appear as a result of big changes in a short period of time

New species appear as a result of big changes over a short period of time



Please please helpppp!!!

Answers

Answer: New species appear as a result of big changes over a short period of time

Explanation:

What condition is MOST likely to spread an illness between people

Answers

Answer:

What are the options?

Explanation:

NaHC3 is an example of what

Answers

Answer: sodium bicarbonate

Answer:

Baking Soda (sodium Bicarbonate, NaHCO3) Is An Example Of A Base.

Explanation:

What would be the expected response to a skin injury if the involved tissue had lost the normal cell characteristic of contact inhibition

Answers

Answer:

uncontrolled excessive growth of cells in the tissue

Explanation:

Contact inhibition is a cellular mechanism where cell growth is arrested when adjacent cells are in contact with each other. Contact inhibition serves to arrest further cell growth beyond a monolayer, by limiting the migration and/or proliferation of cells in a tissue or organ. In consequence, contact inhibition is critical for normal cells to stop proliferating. When contact inhibition is disrupted, cells undergo uncontrolled growth, which leads to the development of cancer and tumor progression.

Which method of food production is sustainable?
A. Planting only a single type of crop
B. Improving food storage facilities
c. Overusing antibiotics on livestock
D. Practicing intensive farming

Answers

Answer:

Improving food storage facilities

If there will be changes on trophic levels, what will be the effects on the ecosystem?

Answers

Answer:

It can significantly alter the homeostasis of the ecosystem

Explanation:

The trophic level is the position that occupies a given organism/ population/species in the food web. In a food web, the trophic levels are organized into a first category (formed by primary producers, e.g., plants), a second level (primary consumers, e.g., herbivores), and subsequent categories (predators, e.g., carnivores). The abrupt change in the number of organisms belonging to the same trophic level generally has a negative effect on the ecosystem by modifying the trophic structure of communities. For example, decreasing the number of producers will produce a decrease in the number of primary consumers, thereby altering the homeostasis (equilibrium) of the entire ecosystem. On some occasions, it may eventually lead to the extinction of populations and species.

2. How is primary succession different from secondary
succession? Giveanexampleofaneventthat may lead primary
succession.

Answers

Answer:

Primary succession is basically the start of a brand new ecosystem. This is when pioneer species form and grow like lichens and some grasses. Secondary succession is when the ecosystem is already started and it's continuing to grow. During this time populations of other species begin to inhabit the ecosystem like shrubs and trees and some animals. Both of these processes take years to complete. An example of an event would be a volcanic eruption, and a wild fire.

Explanation:

Answer:

C. Volcanic Eruption

Explanation:

Just got it right on Edge 2023

uses of crush in the farm​

Answers

Answer:

ok i dont understand what that is

Explanation:

Answer: The overall purpose of a crush is to hold an animal still to minimise the risk of injury to both the animal and the operator while work on the animal is performed.

What is the main force of evolution?

Answers

Answer:

We have to evolve or we will just slowly die off.

In sexual reproduction, a sperm cell fertilizes an egg to form a zygote

A. True

B. False

Answers

it’s true !!!!!!!!!!!!!

Answer:

binary fission

Explanation:

(I will give a Brainliest) Can liquid water and steam exist at 100°C?

Answers

Yes It can.

Hope it helps (:

Answer: yes it can!

Explanation: hope you get a good grade!

explain the process of digestion abd absorption of carbohydrates.​

Answers

Explanation:

the food u eat will goes from oesophagus to ur stomach and then it is mixed by hcl present in your stomach that makes the medium acidic for pesin to digest protein and then bile juice from liver makes the medium alkaline and breaks the larger globules of carbohydrates for enzymes then the food goes goes to small intestine that secretes intestinal juice that converts carbohydrates into glucose

Which atom is involved in giving your heart energy to beat?
O carbon
O gold
O oxygen
O iron​

Answers

Answer:

Oxygen

Explanation:

-How fast the heart beats depends on the body's need for oxygen-rich blood. At rest, the SA node causes your heart to beat about 50 to 100 times each minute. During activity or excitement, your body needs more oxygen-rich blood; the heart rate rises to well over 100 beats per minute.

-The heart, like any organ, requires blood for oxygen and other nutrients so it can do its work. The heart does not gather oxygen or nutrients from the blood flowing inside it. Instead, it receives blood from coronary arteries that eventually carry blood into the heart muscle.

Where does precipitation occur in the water cycle?

Answers

Answer:

i think precipitation mostly occurs in the clouds

PLEASE HELP ASAP (; question in photo

Answers

Answer:

im like 99% sure its D

Explanation:

im sorry if its wrong :(

i think it’s c, exptotential groth.. sorry if i’m incorrect

Energy of activation ________. a. is the energy required for molecules to react with each other b. requires the use of enzymes c. allows for feedback inhibition d. acts on the products of metabolic reactions

Answers

Answer:

a. is the energy required for molecules to react with each other

Explanation:

Activation energy may be defined as the extra energy required to start a reaction and the conversion of reactants into its products. It is the energy required to energize or activate molecules or atoms to undergo a transformation or a chemical reaction.

It is necessary for all types of chemical reaction to proceed. With the help of a catalyst the reaction rate increases as the energy of activation lower for the reaction to start.

1. Rhizobium has symbiotic association with

Answers

Answer:

any one got snap??

Explanation:

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