Question

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 44 to 50.

Social parasitism involves one species relying on another to raise its young. Among vertebrates, the best known social parasites are such birds as cuckoos and cowbirds; the female lays egg in a nest belonging to another species and leaves it for the host to rear.

The dulotic species of ants, however, are the supreme social parasites. Consider, for example, the unusual behavior of ants belonging to the genus Polyergus. All species of this ant have lost the ability to care for themselves. The workers do not forage for food, feed their brood or queen, or even clean their own nest. To compensate for these deficits, Polyergus has become specialized at obtaining workers from the related genus Formica to do these chores.

In a raid, several thousand Polyergus workers will travel up to 500 feet in search of a Formica nest, penetrate it, drive off the queen and her workers, capture the pupal brood, and transport it back to their nest. The captured brood is then reared by the resident Formica workers until the developing pupae emerge to add to the Formica population, which maintains the mixed-species nest. The Formica workers forage for food and give it to colony members of both species. They also remove wastes and excavate new chambers as the population increases.

The true extent of the Polyergus ants' dependence on the Formica becomes apparent when the worker population grows too large for existing nest. Formica scouts locate a new nesting site, return to the mixed-species colony, and recruit additional Formica nest mates. During a period that may last seven days, the Formica workers carry to the new nest all the Polyergus eggs, larvae, and pupae, every Polyergus adult, and even the Polyergus queen.

Of the approximately 8,000 species of ants in the world, all 5 species of Polyergus and some 200 species in other genera have evolved some degree of parasitic relationship with other ants.

The author mentions cuckoos and cowbirds in line 2 because they

A. share their nests with each other

B. are closely related species

C. raise the young of their birds

D. are social parasites

Answer 1

Đáp án D

Thông tin: Among vertebrates, the best known social parasites are such birds as cuckoos and cowbirds; the female lays egg in a nest belonging to another species and leaves it for the host to rear.

Dịch nghĩa: Trong số các loài có xương sống, ký sinh trùng xã hội nổi tiếng nhất là các loài chim như chim cu cu và năng chìa vôi con; con cái đẻ trứng trong tổ thuộc một loài khác và để lại nó cho các chủ tổ để nuôi dưỡng.

Như vậy chim cu cu và năng chìa vôi con được nhắc đến như là một ví dụ điển hình cho các loài kí sinh. Phương án D. are social parasites = là ký sinh trùng xã hội; là phương án chính xác nhất.

          A. share their nests with each other = chia sẻ tổ của chúng với nhau.

          B. are closely related species = là các loài có liên quan chặt chẽ.

          C. raise the young of their birds = nuôi con của các loài chim của chúng.