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Multiple Choice
In sexually reproducing species, the chromosome number remains stable over time because __________ and __________ always alternate.
A
meiosis; mitosis
B
mitosis; fertilization
C
meiosis; interphase
D
meiosis I; meiosis II
E
meiosis; fertilization
Verified step by step guidance
1
Understand the role of meiosis in sexually reproducing species: Meiosis is a type of cell division that reduces the chromosome number by half, creating gametes (sperm and eggs) with a haploid number of chromosomes. This is crucial for maintaining the stability of the chromosome number across generations.
Recognize the importance of fertilization: Fertilization is the process where two haploid gametes (one from each parent) combine to form a diploid zygote. This restores the diploid chromosome number, ensuring that the offspring have the same chromosome number as the parents.
Identify the alternation between meiosis and fertilization: In sexually reproducing species, meiosis and fertilization alternate in the life cycle. Meiosis reduces the chromosome number, while fertilization restores it, maintaining a stable chromosome number over time.
Consider why other options are incorrect: Mitosis is a process of cell division that maintains the chromosome number, not reducing it, so it does not contribute to the alternation needed to stabilize chromosome numbers in sexually reproducing species.
Conclude with the correct answer: The alternation of meiosis and fertilization is essential for maintaining the chromosome number in sexually reproducing species, as meiosis reduces the chromosome number and fertilization restores it.