Questions

Fear of places and situations that might cause panic, helplessness or embarrassment is called Agoraphobia. 

Fear of crossing road causes some panic in them and comes under Agoraphobia.

The process by which bacteria convert nitrogen gas (N2) into ammonia (NH3) is called Nitrogen Fixation.

The conversion of nitrogen from one form to another in the nitrogen cycle is carried out primarily by Nitrogen Fixing Bacteria such as Azotobacter.

( int t ; t = a, a = b, b = t ;);

This code won't compile since declaration of t cannot occur within parentheses.

Stamps are what travel around the worldstaying in one spot. Slippers and walking stick can also travel around the world but they will not stay at one spot. So they are eliminated.

Jean Piaget was a cognitive psychologist who identified four stages of development: the sensorimotor stage from birth to 2 years, the preoperational stage from age 2 to age 7, the concrete operational stage from age 7 to 11, and the formal operational stage from age 11 to adult. He identified milestones that occur at each stage.

According to Piaget, the main task of the sensorimotor stage is for the child to learn the concept of object permanence, use senses and motor skills to understand the world.

Caspian Sea (371,000 sq km)