Explain how the xylem are adapted to their function, in what ways are the gill filaments of fish adapted to their function, and account for the change in zebra population between points R and S on the

14. Explain how the xylem are adapted to their function. (1mk)
Xylem vessels are hollow and continuous tubes for efficient transport of water and mineral salts. Their walls are lignified to provide structural support and prevent collapse.

15. In what ways are the gill filaments of fish adapted to their function? (2mks)
Gill filaments have a large surface area due to numerous folds, a thin epithelium (one cell thick), and a rich blood supply (extensive capillary network). These adaptations ensure a short diffusion distance and maintain a steep concentration gradient for efficient gaseous exchange.

16. The graph below represents a population growth curve of zebras in a grassland ecosystem over a period of time.

a) Account for the change in zebra population between points R and S on the growth curve.
Between points R and S, the population growth rate slows down. This occurs as the population approaches the carrying capacity of the ecosystem. Factors such as limited resources (food, water, space), increased competition, higher predation rates, and accumulation of waste products begin to restrict population growth. The birth rate decreases, and the death rate increases, causing the population to grow at a slower pace.