What cause-and-effect relationship is described in this article?

Question

Ostriches team up with zebras because each species has trouble identifying predators on its own.
Ostriches team up with zebras because zebras can see their predators better in the tall grass.
Cattle egrets team up with water buffalo because egrets eat the insects off the water buffalo.
Cattle egrets team up with water buffalo because the buffalo eat the insects that bite egrets.

Answer 1

Ostriches team up with zebras because zebras can see their predators better in the tall grass.

Answer 2

that answer is incorrect

Answer 3

Ostriches team up with zebras because each species has trouble identifying predators on its own.