Answer:
Adaptations develop when certain variations or differences in a population help some members survive better than others. The variation already exist with the population, but the variation comes from a mutation, or a random change in an organism's genes.
Answer:
Adenine pairs with Thymine or Uracil, Cytosine pairs with Gaunine
Explanation:
In DNA it's Adenine and Thymine but once DNA is transferred to RNA during transcription, Thymine turns into Uracil. Cytosine and Gaunine stay the same throughout the process.
B. the contraction and relaxation of the brain
