The possible genotypes are 50% heterozygous Tt 50% homozygous tt 0% they will have homozygous dominant genotype both genotypes have equal probability to occur because both are 50 50
Cretaceous extinction also known as Paleogene extinction was a period of time when suddenly around three quarter of the animal and plant species began to get extinct from the land. The event happened around 66 million years ago and is considered as the end of cretaceous era that lead to the beginning of Mesozoic era.
Reasons for the mass extinction:
- Scientists think that a major asteroid or comet hit the surface of earth which deteriorated the earth’s environment, especially by making it difficult for plants to perform the process of photosysnthesis. This is called as Impact hypothesis and scientists think that it was the reason of extinction of so many species because they found debris of asteroid in the land.
- There could also be some other reasons like climate changes,volcanic eruptions and changes in the sea level which made the environment unfavorable for the survival of living organisms.
- One of the best known organism that is thought to extinct in cretaceous period was dinosaur.
Extinction of Dinosaurs:
As stated above the exact cause of dinosaur extinction can not be stated with confidence. This is because cretaceous period was the time when so many unfavorable circumstances took place like diseases, geologic events ,climate change etc.
However, the most believed theory is that some Asteroid hit the surface of earth and turned the climate very very old. Therefore, those amazing creatures were not able to survive that climate.
Hope it help!
Ans.
There are twenty amino acids that take part in protein synthesis. These amino acids act as precursor for all protein molecules and are known as essential amino acids. Plants can synthesize all twenty amino acids from simple precursors, while animals can make only twelve amino acids. Animals obtain remaining eight amino acids by eating plants.
Thus, the correct answer is 'option) D.'
<em>Answer:</em>
<em>Phospholipids form the basic structure of a cell membrane, called the lipid bilayer. Scattered in the lipid bilayer are cholesterol molecules, which help to keep the membrane fluid consistent. Membrane proteins are important for transporting substances across the cell membrane</em>
Clean Air Act (CAA), US Federal law, passed in 1970 and later amended, to prevent air pollution and thereby protect the ozone layer and and promote public health. The clean air act gave the federal environmental protection agency the power it needed to take effective action to fight environmental pollution. Hope this helps シ
