Fill blank (ii).

Directions: In the following passage, at certain points you are given a choice of four words.

Grand Canyon is a large river in Arizona. It is known for its magnificent colours. It is made up of layers of rock. The climate there is primarily that of a desert, with both high and low temperatures. Dust storms and smokes from fires change the air. It is __(i)__ to variety of plants and animals. __(ii)__are number of species of special cactus and pine forests. Native Americans have inhabited the __(iii)__ for 3000 years. Today the canyon is a __(iv)__ of the Grand Canyon National __(v)__. About five million tourists visit the park each year.