Answer:
The correct answer will be option-A.
Explanation:
During anaphase, the spindle microtubules help the segregation of the chromosomes from the center of the cell at the metaphase plate.
These microtubules get attached to the chromosomes at kinetochore which helps in pulling of the chromosomes to opposite poles. The microtubules pull apart the sister chromatids when cohesin proteins degenerate.
The chromosomes do not show jiggling movement at the metaphase plate and thus, option-A is the correct answer.
Answer:
Because Tay Sachs is a recessive gene.
Explanation:
It takes two donors both with a recessive gene for the gene to express itself. In this case, two people both with the recessive Tay Sachs disease would have to have children. But when people marry who have the trait, the recessive gene, the recessive can be passed on through to the next generation and so on.
Primary succession occurs at places where there was no vegetation or life before, usually places such as lava or places where glaciers were. Secondary occurs at places that have already previously been colonized, but the habitat was somehow disturbed or damaged.
Depending on what trait the alleles carry, the brothers will have a different phenotype and a different genotype.
For example; Eye color. My sister is heterozygous, meaning she has brown eyes. I am homozygous recessive, meaning I have blue(green/hazel) eyes. We both have the same parents, I just happened to inherit both of the recessive eye color alleles from my parents whereas, my sister inherited both the dominant and recessive alleles.
So, since the brothers inherited different sets of alleles, their genotype for a certain trait will be different.