What is osteoporosis? Name two factors which are responsible for
osteoporosis.

Osteoporosis (or porous bone) is a disease in which bones become weak and, therefore, are more likely to break. It is mostly caused  by the calcium deficiency in the diet. It can be cured by taking diet rich in calcium, by doing regular exercise etc.
It is caused due to various reasons:
1. Low level of estrogen in females after attaining menopause.
2. Improper lifestyle lacking exercise and developing unhealthy eating habits.