Option D – amphibians may use their skin for gas exchange is the characteristic feature of amphibians that differs from reptiles.
Explanation:
The amphibian skin is moist, thin and marbled and supplied by blood vessels running on its surface. The moisture present in the skin dissolves the oxygen present in its surrounding which is absorbed by the blood vessels. Special glands help the amphibians to keep the skin moist.
The very thick and tough scales present on the reptiles prevent them to absorb oxygen through their skin. Hence, they breathe and respire through their lungs.
Amphibians have three-chambered heart. They do not develop amniotic eggs. Adult amphibians although spend much time on land, they breed only in water due to the absence of amniotic sac
.
Answer: I believe it is Thigmotropism.
The plants that were allowed to self pollinate were the F1 plants.
The plants that are true breeding are P generation plants.
The plants where there were 3times as many tall plants as short plants are in F2 generation.
<h3><u>Explanation:</u></h3>
This question is based on the Mendel’s Experiment. Sir Gregor Johann Mendel was the father of genetics who experimented on garden pea plants <em>Pisum</em> <em>sativum</em> to see whether the characters got mixed or not and to know the real cause behind different traits of same character in plants.
He took the pure homozygous tall and short plants separately which he called as parental generation or P generation. These plants were homozygous, hence pure breeding.
As these plants were crossed between themselves, then the F1 generation showed all tall plants. This is because of the heterozygous plants which showed character of dominant trait. These plants were allowed to self pollinate.
As a result of self pollination of the F1 plants, the F2 plants were 75% tall in number whereas the other 25% short, which gave the phenotypic ratio of 3:1.
