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atroni [7]
3 years ago
6

With advancing age, __________ become less responsive to antigens. Additionally, __________ are less responsive, and antibody le

vels do not rise as quickly after antigen exposure.
Biology
1 answer:
diamong [38]3 years ago
7 0

Answer:

1. T cells

2. B cells

Explanation:

With increased age, people become more prone to all infections and produce fewer responses for vaccines. This is due to the lowered levels of function of immune systems against the infections.

With increased age, thymus atrophy and/or hyposecretion of hormones from thymus gland result in reduced activity of T cells against infections. Less number of T cells respond to infections.

The reduced T cell production also makes the B cells less responsive. Reduced responses of B cells towards infection results in slower immune response as antibody levels do not rise quickly.

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const2013 [10]

Answer:

B, it depletes native fish populations

4 0
4 years ago
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Sexual reproduction in eukaryotes increases genetic variation. In prokaryotes, transformation, transduction, and conjugation are
stealth61 [152]

Answer:

A

Explanation:

All living organisms pass on or transfer their genetic material to their offsprings. However, this transfer of genes occurs through the process of reproduction (sexual or asexual). Reproduction may (in case of sexual) or may not (in case of asexual) ensure genetic variation among species.

Eukaryotes that undergo sexual reproduction increase genetic variation among their species by undergoing Crossing-over (exchange of chromosomal segment between non-sister chromatids of homologous chromosomes) during meiosis or gamete formation. This process of transferring genetic material directly from parents to offsprings is called VERTICAL GENE TRANSFER, and only sexual-reproducing eukaryotes ensure genetic variation through this process.

On the other hand, prokaryotic organisms cannot undergo sexual reproduction, they undergo asexual reproduction instead and asexual reproduction does not guarantee genetic variation since identical daughter cells as the parents are produced from the process. However, to promote genetic variation among their species, they employ the processes of transformation, transduction and conjugation which are all forms of HORIZONTAL GENE TRANSFER because it involves transfer of genetic material from one cell (donor) to another (recipient) which do not have the parent-offspring relationship.

7 0
3 years ago
In ducks, the trait for normal feathers is dominant to the trait for silky feathers. If
vesna_86 [32]

Answer: The genotype ratio is 2Ff : 2ff

The phenotype ratio is two normal feathered birds to two silky feathered birds.

Explanation: Let F represent the gene for normal feather and f represent the gene for silky feather. F is dominant while f is recessive, therefore a male that is hybrid for trait of normal feather is heterozygous and will have a genotype of Ff, a female that is homozygous for silky feather will have a genotype of ff.

A cross between Ff and ff will yield 2Ff birds and 2ff birds. Since F is dominant, a bird having genotype of Ff will manifest outwardly as blue feathered birds while ff will manifest outwardly as silky feathered birds because f is recessive and must occur in a homozygous condition in order to manifest phenotypically. Therefore, the genotype ratio is 2Ff: 2ff.

See the punnett square attached for more information

5 0
3 years ago
Help me plz I need help !!!
Anna11 [10]

Answer:

A

Explanation:

mitosis plus answer b and c are the same so those can't be correct.

8 0
4 years ago
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How does the membrane of the cell differ from the nuclear membrane? what advantages does this difference have for the nucleus?
nikklg [1K]
The cell membrane is what controls what goes inside and out the cell meanwhile the nuclear membrane <span>surrounds the genetic material and nucleolus in eukaryotic </span><span>cells. The advantages for the nucleus is that it controls the cell.

</span>
5 0
3 years ago
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