What kind of levers are your arms and legs

Legs are the 2nd class lever.

Arms are the 3rd class lever.

Explanation:

A lever is an inflexible body fit for turning on a point on itself. There are three types of lever

1) 1st class lever:  (pivot is in the center of load and effort)

In the human body are uncommon. One model is the joint between the head and the principal vertebra                    

2) 2nd class lever: (load is in the center of pivot and effort)

In the human body, the 2nd class lever is found in the lower leg when somebody remains on tiptoes.

3) 3rd class lever: (The load is far from the pivot than the effort.)

In the human body; one model can be delineated in the elbow joint

causes

fossil fuels burn

cities become more industrialized

human population grows worldwide