Step-by-step explanation:
Differences in temperature lead to variations in air pressure around the world. Low-pressure areas are created when air rises. It is called low pressure because the weight of the air above the Earth's surface is lower than average. High-pressure areas are created when air sinks. It is called high pressure because the weight of the air is above average when it sinks to the Earth's surface.
Low-pressure areas are associated with cloud and precipitation (rainfall) because:
as the air rises it cools, condenses and forms clouds
the water droplets in the clouds increase in size
they eventually become too heavy to be held and fall as precipitation
The air above the Equator is very hot and rises, creating an area of low pressure. The Equator experiences high amounts of rainfall due to this rising air resulting in a warm and wet equatorial climate (eg the Amazon and Congo tropical rainforests).
High-pressure areas are associated with dry, warm and settled weather conditions. This is because sinking air does not result in precipitation.