Question 17-19: Read the passage and answer the following question and circle the letter A, B, C or D to indicate the correct answer to each of the following questions.

Ants are incredible creatures. Each colony has its own smell. Each of the ants in the colony knows the smell. Enemies will not be able to enter their camp without being discovered. Several types of ants have a sting to protect their nest when strangers get in.
The queen ant is the only one who can lay eggs for the colony. None of the other ants can lay eggs at all. The worker ants cannot lay eggs. They take care of new-born baby ants. They also search for food. These worker ants protect their nest from enemies. They also keep the nest spick and span. They take out the “trash” from the nest and place it in one area.
Slave-maker ants rob the nest of other ants. They steal the pupae, the cases that hold the ant eggs. Then they bring the pupae back to their camp. When the stolen cases hatch, these stolen become slaves.

Câu hỏi

What do several types of ants have to protect their nest when strangers get in?