The polymerase chain reaction makes DNA fingerprinting more reliable because it allows scientists to quickly make many copies of DNA the answer is C
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
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These animals were preyed upon by equally large carnivores such as saber toothed cats, cave bears and dire wolves.
Btw it's (QUATERNARY) *
Answer:
B. 25%
Explanation:
Assuming the trait for teeth size is represented by the allele A. large teeth size is dominant and will be represented by A while small teeth size will be represented by a.
Assuming that the population of 1,000 [piranhas are all heterozygotes and they crossbreed with one another:
Aa x Aa = AA, Aa, Aa and aa
The ration of piranhas with large teeth to that of the small teeth is 3:1 or 75:25.
Hence, about 25% of the next generation of the population is ecpected to have small teeth.
The correct option is B.