When do chromosomal mutations usually appear?
a
when organisms reproduce asexually
b
gradually, in response to abnormal environmental conditions
c
suddenly, as a result of a mistake in mitosis or meiosis
d
as a result of certain diseases
The correct answer is option c: suddenly, as a result of a mistake in mitosis or meiosis.
Chromosomal mutations are usually the result of errors that occur during the processes of mitosis or meiosis. Mitosis is the process by which cells divide and produce two identical daughter cells, while meiosis is the process of producing gametes (sperm or eggs) with half the normal number of chromosomes.
During mitosis or meiosis, mistakes can occur such as nondisjunction, which is the failure of chromosomes to separate properly. Nondisjunction can lead to an unequal distribution of chromosomes in the resulting cells, causing chromosomal mutations.
These mutations can occur suddenly and randomly, without any particular pattern or response to environmental conditions. They can happen in any organism, including those that reproduce asexually or sexually.
Therefore, option c is the correct answer as it best describes when chromosomal mutations usually appear.