The right answer is D (less responsive to antigens)
It is proven that, after puberty, thymus activity (an organ that is included in the lymphatic system, producing T cells that pick up antigens) decreases and that in adult and aged people the thymus has no role. Work done in humans indicate that in fact the cellularity begins to decline from birth in favor of lymphocyte perivascular spaces and connective and adipose tissue, which leads to a decrease in the capture of antigens.
The answer is C) Increase genetic variation and breed plants to contain the wild variety.
The randomness in the alignment of recombined chromosomes at the metaphase plate, coupled with the crossing over events between nonsister chromatids, are responsible for much of the genetic variation in the offspring. To clarify this further, remember that the homologous chromosomes of a sexually reproducing organism are originally inherited as two separate sets, one from each parent. Using humans as an example, one set of 23 chromosomes is present in the egg donated by the mother. The father provides the other set of 23 chromosomes in the sperm that fertilizes the egg. Every cell of the multicellular offspring has copies of the original two sets of homologous chromosomes. In prophase I of meiosis, the homologous chromosomes form the tetrads. In metaphase I, these pairs line up at the midway point between the two poles of the cell to form the metaphase plate. Because there is an equal chance that a microtubule fiber will encounter a maternally or paternally inherited chromosome, the arrangement of the tetrads at the metaphase plate is random. Thus, any maternally inherited chromosome may face either pole. Likewise, any paternally inherited chromosome may also face either pole. The orientation of each tetrad is independent of the orientation of the other 22 tetrads.
Explanation:
Answer:
<em>I think the answer might be oxygen</em>
Explanation:
<em>I think this because you need oxygen to survive. Right?!</em>
Answer:
Calcification, or mineralization, then occurs when hydroxyapatite crystals deposit in the bone matrix.
Explanation:
Calcification -
It is the situation of the accumulation of the salts of calcium in the tissues of the body , is known as Calcification .
This process usually occurs during the bone formation , but in abnormal condition the soft tissues of the body gets harden , leading to the situation of Calcification , it is also known as mineralization .
The crystal deposited are of hydroxyapatite in the bone matrix .