Because each parent contributes to their child 23 chromosomes, so therefore each parent gives their child half of the DNA of the child.
It wouldn't be 30% or 70% because the balance of the chromosomes the parents contribute is always equal.
A.)
The student had to assume that starch was made from the glucose created in photosynthesis in order to conclude that no starch was present in the leaf areas that lacked chlorophyll and could not perform photosynthesis.
Answer:
by using molecular clocks which are based on the mutation rates among molecular sequences (e.g., DNA sequences). The mutation rate can be used to estimate the times of divergence between sequences (in this case, between duplicated sequences in the target species and non-duplicated sequences in the most recent common ancestor).
Explanation:
A molecular clock is a technique that uses the mutation rate (μ) to measure the association between evolutionary rate and time. A mutation rate can be used to estimate the time in prehistory when two or more molecular sequences diverged. For example, assuming a generation time of 20 years, a species that has 100 mutations per generation is divided by 20 years to yield a mutation rate equal to 5 mutations per year. In consequence, the times of divergence can be estimated by dividing half of the target genomic region length (in nucleotides) by the mutation rate (t = d/2 ÷ μ).