Which two activities happen as the embryo grows? A. The cells decrease in number.
B. The cells form new organisms.
C. The cells rearrange molecules.
D. The cells divide.

100 point better give me right anwser pleaseee

Classify the structures as homologous or analogous, depending on their structure and function.

How is ribosomal rna useful as a molecular clock? a. a large portion of the dna ring is not vital to structure or function, allowing it to accumulate neutral mutations. b. its rate of mutation increases over time as organisms continue to evolve and differentiate from each other. c. a slow mutation rate makes it useful for determining evolutionary relationships between ancient species. d. it is only found in select organisms, making it easier to compare relationships between species that have it.

Ialready know the answers to these questions and they are on the attachment. but i just need to know why that answer is the correct one. plz asap! this is for a report that i need to email by 10!