Answer:
The process in cell division by which the nucleus divides, typically consisting of four stages, prophase, metaphase, anaphase, and telophase, and normally resulting in two new nuclei, each of which contains a complete copy of the parental chromosomes.
The earth is about 6,000 years old.
Ans.
Sex-linked genes are those genes that found on sex-chromosomes (X and Y chromosomes) and their phenotypic expression for a trait depends on the gender of the offspring.
Most of the sex-linked genes are present on X chromosomes as X chromosomes have more number of genes as they are made up of more DNA as compared to Y chromosome.
However, male individuals are more likely to exhibit the sex-linked traits. It is because most of the sex-linked traits are recessive and males have only one copy of X chromosome, while females have two copies of X chromosome. One mutated copy in male can exhibit the trait, while in females, both of the mutated copies are required to exhibit that trait.
Specialised cells I think
Insufficient nutrient, lack of water, no sunlight, climate change, pollution