Concept explainers
Introduction:
The meiosis is known as the reductional division. The chromosome number gets reduced in meiosis from 46 chromosomes to 23 chromosomes. It is important in reproduction. It occurs at the time of spermatogenesis and oogenesis.

Answer to Problem 1A
Correct answer:
During the human life cycle, the meiosis process is responsible for reducing the number of chromosomes from 46 to 23 found in the gametes. Therefore, option (d) is correct.
Explanation of Solution
Reason for the correct statement:
The meiosis is a process in which the chromosome number gets reduced from 46 chromosomes to 23 chromosomes. Hence, meiosis is also known as a reductional division.
Option (d) is given as “meiosis”.
As “the meiosis process is responsible for reducing the number of chromosomes from 46 to the 23 found in the gametes”, it is the right answer.
Hence, option (d) is correct.
Reasons for the incorrect statements:
Option (a) is given as “mitosis”.
In mitosis, the chromosome number remains the same (46 chromosomes). Mitosis is the duplication division, in which each daughter cell maintains its chromosome number. It did not reduce the number of chromosomes, so it is an incorrect answer.
Option (b) is given as “fertilization”.
Fertilization is a process in which haploid male and female gamete fuse with each other and form diploid zygote. It did not reduce the number of chromosomes, so it is an incorrect answer.
Option (c) is given as “ovulation”.
Ovulation is a process in which the secondary oocyte releases from the secondary mature follicle. It did not reduce the number of chromosomes, so it is an incorrect answer.
Option (e) is given as “None of these are correct”.
Meiosis is a process in which the chromosome number gets reduced from 46 chromosomes to 23 chromosomes. So, it is an incorrect answer.
Hence, options (a), (b), (c) and (e) are incorrect.
During the human life cycle, the meiosis process is responsible for reducing the number of chromosomes from 46 to 23 found in the gametes.
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Chapter 17 Solutions
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