What s a difference in the same trait.

Alleles are versions of the same gene with slight variations in their sequence of DNA bases. These small differences among alleles of the same gene contribute to each person's unique characteristics

Explanation:

option a is correct i.e.

explanation:

in context to the membrane of nerve impulse, the outer membrane of neuron is semi permeable that is only sodium ions can pass through the membrane i.e. smaller ions can pass through the membrane while larger ions cannot pass through it.

b - the respond is innate and varies over time.

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