Answer: The correct answer is- A. Chromosome numbers vary widely.
Chromosome can be described as thread like structure that is composed of DNA ( deoxyribonucleic acid) and possesses genes ( segment of DNA coding for a particular protein) on it.
Eukaryotic cells ( such as plant cell, animal cell) have variable number of chromosomes.
For instance, human beings have 23 pairs of chromosomes whereas it is different in plants depending on the species.
Thus, A) is the right answer.
The appropriate response is Mountain ranges. It is a progression of mountains or slopes went in a line and associated with high ground. A mountain framework or mountain belt is a gathering of mountain ranges with closeness in shape, structure, and arrangement that have emerged from a similar reason, as a rule an orogeny.
Answer:
The trachea, commonly known as the windpipe, is a most important organ as it allows the passage of air into the lungs. Because the trachea has a soft tissue tubular formation, it needs a base of stronger, yet flexible stuff that will give it support, protect it, and still allow the passage of air into the lungs.
This is precisely the task of the tracheal rings, or cartilage rings in the trachea. These rings are made out of cartilaginous tissue, which is much stronger than the soft tissue of the tubule, but are still flexible enough to not close down the tube when air is flowing in. Thus, the tracheal rings have two tasks: one, provide support and protection for the much softer and more vunerable tube of soft tissue through which the air passes, and two, provide flexibility so that air can flow easily.
If these tracheal rings did not exist, if they are crushed, or removed, a person´s trachea would simply collapse and the person would die as air would not be able to flow through to the lungs.
Answer: Genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).
By the end of meiosis, the resulting reproductive cells, or gametes, each have 23 genetically unique chromosomes. The overall process of meiosis produces four daughter cells from one single parent cell.
Explanation:
During meiosis, homologous chromosomes (1 from each parent) pair along their lengths. The chromosomes cross over at points called chiasma. At each chiasma, the chromosomes break and rejoin, trading some of their genes. This recombination results in genetic variation.
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<em>Organ donation is nothing but the process by which the person donates his/her organ to other person to save the life of a him/her.</em>
