T cells
The immune response to a transplanted organ consists of both cellular (lymphocyte mediated) and humoral (antibody mediated) mechanisms. Although other cell types are also involved, the T cells are central in the rejection of grafts. The rejection reaction consists of the sensitization stage and the effector stage.
Answer:
The heart is a pump, usually beating about 60 to 100 times per minute. With each heartbeat, the heart sends blood throughout our bodies, carrying oxygen ... It sends out an electrical signal to start the contracting (pumping) of the heart muscle.
Explanation:
Answer: False
<span>Genes do play a role in the development of obesity but a genetically predisposed person can still improve his overall health through moderate lifestyle changes.</span>
<span>Obese people may change their weight slowly by altering lifestyle habits with the support of their family and friends. Even if weight remains unchanged, overall health will improve with moderate lifestyle changes.</span>
Answer:
D.Mendel's law of independent assortment is being violated.
Explanation:
According to Mendel in his law of independent assortment, the allele of one gene gets sorted into gametes independently of the allele of another gene. He discovered this when he performed a cross involving two characters i.e. dihybrid cross, which he obtained a F2 phenotypic ratio of 9:3:3:1. This ratio is only possible if each allele of each gene is represented in each gamete i.e. a dominant allele of the first gene is equally likely possible to be contained with a dominant or recessive allele in the second gene.
If this occurs according to the Mendel's law of independent assortment, a total of four possible combinations of gametes should be produced by each parent organism. When this 4 gametes are crossed in a punnet square, a total of 16 offsprings will be possible.
However, in this case, a total of 12 offsprings were produced, depicting that the alleles did not separate independently of one another to produce four possible gametes.
