To prevent blood flowing back after each heartbeat. They ensure that the blood flows only in one direction (back to the heart).
I believe it is either B or A, personally i'm leaning towards B, but at the same time, i don't think that we would be obtaining materials via pollination, so it then causes A to make more sense.
Answer: The correct answer is -
D. They determine the inherited traits of an organism.
Gene can be described as segment of DNA (deoxyribonucleic acid) that codes for particular protien, which determines specific trait (which is an inherited trait) of the organism.
Genes are located on chromosomes as considered as the unit of heredity as they are passed from one generation to the next generation.
Examples for inherited trait include eye color, skin color, hair shape and color etc.
Thus, option D) is the right answer.
<em>B. Has the same allele on both chromosomes in a chromosome pair. </em>
<u>Here is why:</u>
Homozygous means the same, while heterozygous means different. If both of the same alleles are on both chromosomes, then it will be a homozygous.
There can be two types of homozygous alleles.
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<em>Homozygous Dominant</em>: BB
<em>Homozygous Recessive</em>: bb
<u>Notice in both of these they were the same alleles.</u>
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<em>Heterozygous</em>: Bb
<u>Notice how both are different alleles.</u>
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Below I have attached a diagram of a Punnett square I have made.
On the left is a homozygous recessive allele pair.
On the top is a heterozygous allele pair.