Which of the following are key elements of darwin's theory of evolution by natural selection?

Independent assortment and crossing over contribute to diversity within a population's gene pool. These processes occur during meiosis and result in the recombination of DNA.

Explanation:

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image result for how many calories of energy will 20 grams of carbohydrates provide in one gram provides 4 calories

consuming the right balance of protein, carbohydrates and fat can you maintain a healthy weight and optimize your energy levels. protein and carbohydrates both contain 4 calories per gram, while fat provides 9 calories per gram.

im not intirely sure but i think the anwser is d relative humidity