Questions

New Delhi is the most polluted city in the world, according to Air Quality Index 2018.

The nervous system is the part of an animal that coordinates its actions by transmitting signals to and from different parts of its body.

In vertebrates it consists of two main parts, the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal cord. The PNS consists mainly of nerves, which are enclosed bundles of the long fibers or axons, that connect the CNS to every other part of the body.

The nervous system has three main functions:

* To collect sensory input from the body and external environment.

* To process and interpret the sensory input.

* To respond appropriately to the sensory input.

The Indian Space Research Organisation is the space agency of the Government of India was set up in the year 1969, headquartered in the city of Bangalore. Its vision is to "harness space technology for national development while pursuing space science research and planetary exploration.

Sales tax is an additional amount of money you pay based on a percentage of the selling price of goods and services that are purchased.

For example, if you purchase a new laptop Rs. 40000 and live in an area where the sales tax is 6%, you would pay Rs.2400 in sales tax.

The given sentence is in simple present tense and states a general fact, hence the latter half of the sentence with the blank will also be in the simple present tense. Since the subject in the latter part of the sentence is singular .i.e. 'the number', the verb will be followed accordingly. Hence, option 4 is the correct answer.