Final answer:
The statement that females are slightly taller and heavier than males is generally false. In humans, males are typically larger, though there is variation. Sexual dimorphism often relates to reproductive strategies and can impact body size and structure, such as the female pelvic adaptations for childbirth.
Step-by-step explanation:
The question relates to the concept of sexual dimorphism, which is the difference in size or appearance between the sexes of a species beyond the differences in their reproductive organs. In many species, males and females exhibit significant physical differences that are often related to reproductive strategies. For humans, evidence suggests a trend where females are generally smaller than males, though this can vary among individuals.
Considering sexual dimorphism in the context of the human species, the statement that both sexes are similar in appearance, but the female is slightly taller and heavier, is generally false. While there are individual exceptions, on average, females are about 90 percent the size of males, indicating that males are typically larger. This pattern is consistent with other primates, such as gibbons and chimpanzees, though the degree of dimorphism varies among species.
Pelvic differences are an example of sexual dimorphism adapted for reproductive fitness, with females having a lighter, wider, shallower pelvis with a broader angle between the pubic bones to facilitate childbirth. However, this structural adaptation for reproduction does not mean that females are generally taller or heavier than males.