Question

the african savanna is a tropical grassland that supports grazing animals, such as antelopes and zebras. the savanna. small mammals, such as shrews and mice, burrow in soil beneath the grasses. acacia trees are knocked down and eaten by elephants. which of the following is likely to cause the greatest change in the
a. an increase in the lion population
b. a decrease in the elephant population
c. an increase in the shrew population
d. a decrease in the antelope population

Explanation:

To solve this, we analyze the savanna ecosystem. Elephants knock down trees, and small mammals (shrews, mice) live under grass. If elephant population decreases, tree growth might increase, reducing grassland. But the question is about what causes a grassland change. Wait, the key is: Elephants knock down trees, so less elephants would mean more trees, less grass? No, wait, the small mammals live beneath grass. Wait, maybe the problem is about grassland. Wait, the options: A lion increase would affect herbivores, but the focus is on elephants. Wait, elephants knock down trees, so if elephant population decreases (option B), there would be more trees, less grass? No, maybe the grassland is maintained by elephants knocking down trees (so trees don't overtake grass). So if elephants decrease, trees grow, grassland shrinks. But the question is which causes the grassland change. Wait, the small mammals (shrews, mice) live in grass. Wait, maybe the correct answer is B: a decrease in elephant population. Because elephants knock down trees, so fewer elephants mean more trees, less grass (so grassland changes). Let's check options:

A: Lion increase affects herbivores (antelopes, zebras), but not directly grass via elephants.

B: Elephant decrease: elephants knock down trees, so less elephants → more trees → less grass (grassland change).

C: Shrew increase: shrews are small, don't affect grassland structure.

D: Antelope decrease: antelopes eat grass, but the grassland structure (trees vs grass) is affected by elephants.

So the correct answer is B.

Answer:

B. a decrease in the elephant population