Explanation:
The duration of 19-21 days refers to the period of the menstrual cycle soon after menstruation during which fertilization is most likely to occur.
Explanation of other options:
- The incubation period of a hen's egg is about 21 days, not specifically 19-21 days.
- The average lifespan of a human red blood cell is around 120 days, much longer than 19-21 days.
- The schizogony cycle of malarial parasites inside red blood cells typically ranges from 24 to 72 hours depending on the species, not 19-21 days.
Therefore, the correct answer is (C) the period of menstrual cycle soon after menstruation, during which fertilization is most likely to occur.
Explanation by: Mr. Dubey
The duration of 19-21 days refers to the period of the menstrual cycle soon after menstruation during which fertilization is most likely to occur.
Explanation of other options:
- The incubation period of a hen's egg is about 21 days, not specifically 19-21 days.
- The average lifespan of a human red blood cell is around 120 days, much longer than 19-21 days.
- The schizogony cycle of malarial parasites inside red blood cells typically ranges from 24 to 72 hours depending on the species, not 19-21 days.
Therefore, the correct answer is (C) the period of menstrual cycle soon after menstruation, during which fertilization is most likely to occur.