Question

3 animal x grows on the shell of a crab.
(a) animal x has a poisonous sting. explain why it is an advantage for the crab to have animal x growing on its shell.
(b) animal x can also grow on a rock. give a reason why animal x would benefit from growing on the crab instead of growing on a rock.

Explanation:

Advantage of poisonous sting for the crab

The poisonous sting of Animal X (sea anemone) deters or fends off predators of the crab, protecting the crab from being eaten.

Benefit to Animal X of growing on the crab instead of a rock

The crab is mobile, which allows Animal X to move around to find more food sources or obtain leftover food scraps from the crab's meals, whereas a rock is stationary.

Answer:

Question 3(a)

The poisonous sting of Animal X helps to protect the crab by fending off or deterring its predators.

Question 3(b)

The crab can move from place to place, which helps Animal X obtain more food sources or feed on the leftover food scraps from the crab's meals, whereas a rock is stationary.