Reasons why the forthcoming generation may be less adaptive than the parental generation:

- Natural Selection:
Natural selection plays a crucial role in the evolution of species. If the environment changes rapidly, the forthcoming generation may not have had enough time to adapt to these new conditions, leading to decreased adaptability compared to the parental generation.

- Mutation:
Mutations are random changes in an organism's DNA that can either be beneficial, harmful, or neutral. If the forthcoming generation experiences harmful mutations that decrease their fitness in a particular environment, they may be less adaptive compared to the parental generation.

- Genetic Drift:
Genetic drift refers to random fluctuations in the frequency of alleles in a population. If the forthcoming generation experiences genetic drift that reduces genetic diversity, they may be less able to adapt to changing environmental conditions compared to the parental generation.

- Adaptation:
While adaptation is essential for survival, the forthcoming generation may face challenges in adapting to new environments if the changes are too rapid or extreme. Lack of proper adaptation mechanisms can result in decreased adaptability compared to the parental generation.

In conclusion, various factors such as natural selection, mutation, genetic drift, and lack of adaptation mechanisms can contribute to the forthcoming generation being less adaptive than the parental generation. It is crucial for organisms to continuously evolve and adapt to ensure their survival in changing environments.

B)Mutation.