Every person has two copies of each gene, one inherited from each parent. Most genes are the same in all people, but a small number of genes (less than 1 percent of the total) are slightly different between people. Alleles are forms of the same gene with small differences in their sequence of DNA bases. These small differences contribute to each person’s unique physical features.
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Protist<span> manufacture their own energy by photosynthesis (using sunlight)</span>
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For the first question is that crabgrass because in the process of secondary succession a forest fire burns down a forest then grasses grow back, then annual flowers bloom and eventually trees begin to grow so crabgrass is the initial stages of secondary succession.
<span>B. They exist only in the northern hemisphere</span>
