27. Most human cells have 46 chromosomes. How many chromosomes are in a human sperm or egg?
Answer: C
Human sperm or egg cells contain 23 chromosomes.
In humans, sperm and egg cells, which are gametes, each contain 23 chromosomes. This is half the number of chromosomes found in most human cells, which have 46 chromosomes.
A) 92
Option A is incorrect because 92 chromosomes represent the total number of chromosomes in a human cell during the metaphase of cell division, not in gametes. Gametes only carry half the chromosome number to ensure the total is restored upon fertilization.
B) 46
Option B is incorrect because 46 chromosomes are present in somatic cells, not in sperm or egg cells. Gametes must have half the chromosome count to maintain the species' chromosome number across generations.
C) 23
Option C is correct. Human sperm and egg cells are haploid, meaning they contain only 23 chromosomes. This reduction in chromosome number is crucial for sexual reproduction, allowing for the restoration of the diploid number upon fertilization.
D) 12
Option D is incorrect as it underestimates the number of chromosomes in human gametes. A chromosome count of 12 does not align with the established genetic structure of human beings, which requires gametes to have 23 chromosomes.
Conclusion
The correct answer, 23 chromosomes in human sperm or egg cells, is essential for maintaining the proper genetic balance during reproduction. All other options either overstate or understate the necessary chromosome count, thus failing to reflect the biological principles of human genetics.