Question

question 1-19
which of the following statements best explains the role of meiosis in reproduction?
meiosis makes it possible for a zygote to have the correct number of chromosomes.
meiosis increases the chances of fertilization because it produces four daughter cells.
meiosis results in offspring with genotypes that are not exact copies of the parents
meiosis allows chromosomes to exchange genetic material through crossing over.

Explanation:

1. Analyze Option 1: Meiosis reduces the chromosome number by half in gametes. When a haploid gamete (from meiosis) fuses with another haploid gamete during fertilization, the zygote gets the correct diploid number of chromosomes. This is a key role of meiosis in sexual reproduction to maintain chromosome number across generations.
2. Analyze Option 2: The number of daughter cells (four) from meiosis does not directly increase fertilization chances. Fertilization depends on gamete meeting, not just cell quantity. So this is incorrect.
3. Analyze Option 3: While meiosis does contribute to genetic variation (which leads to non - identical offspring), the primary role related to reproduction's basic mechanism (chromosome number maintenance) is more fundamental. Also, the statement's focus on genotype copying is not the best explanation of its role in reproduction.
4. Analyze Option 4: Crossing over is a process during meiosis that contributes to genetic variation, but it is a part of how meiosis achieves genetic diversity, not the main role of meiosis in reproduction (which is about chromosome number for zygote and sexual reproduction's viability).

Answer:

A. Meiosis makes it possible for a zygote to have the correct number of chromosomes.