Why do we use topographical maps ? what does every map / hill on a topographical map start at & how do you know ?

How do earth’s systems interact with each other?

Scientists are studying hurricanes to determine the number of hurricanes in the past 50 years that have caused greater than $1 million in damages. which best describes the population? hurricanes hurricanes that caused greater than $1 million in damages scientists scientists participating in the research

The torque output of an engine is usually measured in the units of a rpm b bhp c foot pounds d feet per pound