Describe how natural selection can sometimes lead to persistence of harmful or even lethal allele include exampple

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Explanation:

This question may have made it seem like natural selection is a harmful process -- be wary of this. To understand this, you have to note something known as heterozygote advantage. All this means is that the heterozygotes, the organism that expresses both the dominant and recessive alleles, rather than the homozygotes, organisms that express both dominant or both recessive alleles, have an advantage. An example is with sickle cell disease. People heterozygous for the sickle cell trait are more resistant to malaria for some reason, whereas the homozygotes are not. Because heterozygotes (which have a harmful allele and normal allele) have the advantage, natural selection selects for this trait and favors it. This leads to the "persistence of harmful or even lethal allele[s]." Again, just because the organism has a lethal allele isn't necessary always a bad thing. :)

both anaerobic and aerobic respiration use glucose (or other carbohydrates), proteins and lipids to produce atp and nadh. cell uses those energy molecules, obtained from food and   breaks them down during the chemical reactions of respiration. in anaerobic respiration, nadh is regenerated to nad+ by enzymes lactate dehydrogenase (lactate is produced, e.g. in muscle cells) or by alcohol dehydrogenase where ethanol is produced (alcohol fermentation), while in aerobic respiration, electrons from nadh are deposited in the mitochondria to regenerate nad+ (electron transport chain. anaerobic respiration produces 2 atp per molecule of glucose compared to aerobic respiration where about 38 atp molecules are produced.

answer: a) a compound microscope has a greater magnification ability than a simple microscope.

explanation: