Which of the following group of substances is obtained from animal?
Cotton, purse, egg, carpet
Shirt, jacket, chicken, butter
Milk, leather, wool, silk
Rubber, bat, chair, sweater
All these materials are obtained only from animals.
To increase soil fertility, the organic substances obtained from the decomposition of animal wastes are added. This is known as __.
___ charcoal is obtained by removing water and some other volatile constituents from the animal and vegetation substances.