Problem:
Question 1: When does differentiation begin in fruit fly (insects)?
a. Prior to fertilization
b. Just after fertilization, but before any cell divisions take place
c. Just after the first cell division
d. At the blastula stage
e. At the globular embryo stage
Question 2: When does differentiation begin in frog (vertebrates)?
a. Prior to fertilization
b. Just after fertilization, but before any cell divisions take place
c. Just after the first cell division
d. At the blastula stage
e. At the globular embryo stage
Please select correct answer and also provide explaination.