单选题

Which of the following is an example of symbiosis as it is described in Paragraph 2?

A Certain types of tall grass conceal tigers because of the tigers’ striped markings.

B Fish called remoras attach themselves to sharks and eat the scraps of the sharks’ meals.

C Mistletoe, a type of shrub, grows on trees and harms them by extracting water and nutrients.

D Protozoa in the intestines of termites digest the cellulose that the termites eat, and their waste products nourish the termites.

解析：
细节题。由symbiosis（通常指互利的共生现象）定位到第二段第四句“The two organisms live together to the benefit of both, a relationship known as symbiosis.”（这两种有机体为了双方共同利益而共存，因此它们之间的关系被称作“共生现象”），而选项D所描述的“白蚁肠中的原生动物消化吸收白蚁吃下的纤维素，而它们的排泄物又为白蚁提供了营养”正体现了两者之间互利的共生现象。