Read the following statements:

Assertion (A): Some children have characteristics that resemble their parents while others are markedly different from their parents.

Reason (R): Working out how much of any characteristic is due to nature or genes and how much is due to nurture or environment is a complex issue.

Choose the correct option.

To evaluate the given Assertion (A) and Reason (R), let us analyze them step-by-step:

1. Analysis of Assertion (A):
Assertion (A) states: "Some children have characteristics that resemble their parents while others are markedly different from their parents."
This statement is a well-established biological observation. Inheritance of traits through sexual reproduction involves genetic recombination, independent assortment, and crossing over. Consequently, children inherit a unique combination of genes from both parents, leading to some traits being shared (resemblance) and others being novel or different (variation). Thus, Assertion (A) is true.

2. Analysis of Reason (R):
Reason (R) states: "Working out how much of any characteristic is due to nature or genes and how much is due to nurture or environment is a complex issue."
The expression of any phenotype (observable trait) is the result of interaction between an organism's genotype (nature/genes) and its environment (nurture/nurturing conditions). Delimiting the exact contribution of genetic inheritance versus environmental factors is indeed a highly complex task in genetics and psychology. Thus, Reason (R) is true.

3. Evaluation of the connection between A and R:
The variation and resemblance observed in children (Assertion A) are directly explained by the intricate and intertwined roles of genetics (nature) and environment (nurture). Because determining the relative contribution of nature versus nurture is complex (Reason R), we observe a wide spectrum of resemblance and differences among offspring relative to their parents. Therefore, Reason (R) provides the correct explanation for the phenomenon described in Assertion (A).

Consequently, both statements are true, and R is the correct explanation of A.