Each type of human cell has a different structure and function because: A - Scottish Highers Human Biology - Question 1. - 2018

The primary reason that each type of human cell has a distinct structure and function is due to the expression of different genes in each cell type. Although all human cells contain the same DNA, they can show diverse functionality based on which genes are activated or expressed at any given time. For instance, a muscle cell expresses genes that facilitate contraction, while a neuron expresses genes that support neurotransmission.

This differential gene expression is crucial during cellular differentiation, where cells become specialized for specific functions. Therefore, the correct answer is B.