Question

1. the cell cycle is shown in the diagram below.which point in the cell cycle represents its completion before it begins again?a after m phaseb after ( g_1 ) phasec after s phased after ( g_2 ) phase13. which two ways explain how the process of meiosis produces offspring that are genetically different from the parents?a the number of chromosomes is doubled in the offspring so that it has twice as much dna as its parents.b only one parent is needed to produce offspring by meiotic cell division.c the offspring receive genetic material from two parents with different dna.d crossing over during the process of meiosis produces additional variation in the dna.e meiosis preserves the number of chromosomes in the dividing cells so that they remain diploid.

Explanation:

Question 12

The cell cycle consists of interphase (G₁, S, G₂) and M - phase (cell division). After M - phase (mitosis or meiosis), the cell has completed division. The daughter cells then enter G₁ phase of the next cell cycle. So the cell cycle is completed after M - phase.

• Option A: In meiosis, the chromosome number is halved (not doubled) in the gametes. When gametes fuse during fertilization, the diploid number is restored. So this option is incorrect.
• Option B: Meiosis is a part of sexual reproduction which requires two parents (in most cases). Asexual reproduction (like binary fission, budding) requires only one parent. So this option is incorrect.
• Option C: In sexual reproduction (which involves meiosis), offspring receive genetic material from two parents. Each parent has different DNA (except in cases of clones, but in normal sexual reproduction, parents are non - identical). This leads to genetic variation.
• Option D: Crossing - over (exchange of genetic material between homologous chromosomes) during meiosis prophase I produces additional variation in the DNA of the gametes.
• Option E: Meiosis reduces the chromosome number (from diploid to haploid in gametes). Mitosis preserves the chromosome number. So this option is incorrect.

Answer:

A. after M Phase

Question 13