Final answer:
Sexual reproduction is energy-intensive and requires finding a mate, which can be challenging. Only half the population can produce offspring, and while it allows for variation, not all traits may be beneficial for rapid environmental change.
Step-by-step explanation:
Some disadvantages of sexual reproduction include that it is an energy-intensive process because it requires finding and attracting a mate (Option B). This process is not only energy-consuming but also time-consuming, and it can be quite challenging if mates are scarce or widely dispersed. Additionally, in sexual reproduction, only half of the population (females) can produce offspring, in contrast to asexual reproduction where every individual can potentially contribute to the population's growth, making sexual reproduction less effective at rapidly populating an environment. Moreover, while sexual reproduction results in greater variation among offspring (contrary to Option A), this variation can be a disadvantage if the environment changes rapidly, because not all the traits may be beneficial for survival in the new conditions. Thus, while sexual reproduction enables species to adapt over time (which challenges Option D), in the short term, it may not facilitate as rapid an adaptation as asexual reproduction could.