Put the following stages of development in order...
a. Blastocyst implants in uterus,
b. zygote forms,
c. heart begins beating,
d. lungs can breathe air,
e. sex organs become visible

they fuse to form they have half as many chromosomes as a somatic cell of the same individual. b

c) 50% there are four chromosomes. after crossing over, 2 of the four have been changed. that means any gamete has a 2 in 4 chance or 50% chance of receiving the mutated chromosome.

idk and i also need to know where are those bio brainy acts lol