Question

(c) fig. 1.3 shows the events that occur during sexual reproduction in birds. the numbers in brackets indicate the number of chromosomes in the nuclei of the cells of the common emerald dove.
adult male (80)
adult female (80)
process
process
a
a
sperm (40)
egg (40)
cell b (80)
embryo (80)
hatching
young bird (80)
fig. 1.3
(i) name process a and cell b.
a ...............................................................................................
b ...............................................................................................
2

Explanation:

• Process A: In sexual reproduction, the formation of gametes (sperm and egg) from adult cells involves meiosis. Meiosis is a type of cell division that reduces the chromosome number by half. Here, adult cells with 80 chromosomes form gametes (sperm and egg) with 40 chromosomes, which is characteristic of meiosis.
• Cell B: When a sperm (40 chromosomes) and an egg (40 chromosomes) fuse, they form a zygote. The zygote contains the full set of chromosomes (80 in this case) as it combines the genetic material from both the sperm and the egg.

Answer:

A. Meiosis
B. Zygote