Adenine and guanine have a fused-ring skeletal structure derived of purine, hence they are called purine bases. ... Similarly, the simple-ring structure of cytosine, uracil, and thymine is derived of pyrimidine, so those three bases are called the pyrimidine bases.
Firstly they are not membranes and they are villi's which increase the surface area during digestion
What are the experiments?
Answer:
See explanation
Explanation:
According to the theory of evolution,species which are better adapted to their environment tend to survive and reproduce in a population passing on these favourable characteristics to their offsprings.
During sexual reproduction, genes can be arranged in new ways from chromosomal crossing over and recombination. This introduces new gene combinations(genotype) and ultimately variation in the population.
This variation may also lead to the observation of new phenotypes in the population.