What is the main source of downward convection<span> flow in the mantle called? The downward sliding characteristic of ridge-push is the result of what? </span>What causes<span> the </span>thermal convection that drives plate motion<span>? Is it the downward arm of convective flow in the mantle?
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</span>The heat driving<span> mantle </span>convection<span> has three sources. "Primordial" </span>heat<span> (left over from the accretion and differentiation that led to the formation of Earth's core) contributes 20 to 50% of the </span>heat<span>. ... Mantle </span>convection<span> is the main mechanism by which this </span>heat<span> escapes from the interior of Earth.
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Answer:
The correct answer is : option B.
Explanation:
Hardy–Weinberg equilibrium is a mathematical model that states that genotype percentage or frequency in a population and allele in a population remains stable or constant to generations if there are no evolutionary influences present.
Hardy Weinberg equation is :
P²+2pq+q² = 1
Here, p² represents the frequency of genotypes dominant homozygotes (AA) in a population in equilibrium. The term 2pq represents the frequency of heterozygotes (Aa) as there are two ways of developing heterozygous individuals either dominant from the egg and recessive from sperm or vice versa. and the term q² represents the frequency of recessive homozygotes (aa).
Thus, the correct answer is : option B.
Answer:
The chance of a normal couple having a child with down syndrome is 1 to 600 births.
Explanation:
Down syndrome is a genetic flaw that occurs when the fetus is being formed.
A human cell considered normal has 46 chromosomes, divided into 23 pairs. For some unknown reason, an error may occur at the beginning of embryonic development and an extra chromosome is created, which binds to par 21. The result is cells with 47 chromosomes. This causes the said syndrome.
It is important to know that this failure happens at random. It is nobody's responsibility. It has not been proven to date that lifestyle, actions during pregnancy, smoking, drinking, medicines, environmental factors or kinship between the couple can influence this occurrence. She is not contagious either. The likelihood of a normal couple having a child with the syndrome is approximately 1 to 600 births.