Certain nutrients are considered essential in the diets of some animals because .

The animals are not able to synthesize them or they cannot be manufactured even though they are required by the animals.

Explanation:This is because Essential Nutrients are those Substances that must be gotten from the diet because the body cannot make it in sufficient quantity to meet its needs.

Some of these substances are demonstrably desirable in the diet, but do not meet the criteria like being able to be manufactured by the organism.

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