Your respiratory system is the network of organs and tissues that help you breathe. This system helps your  body  absorb oxygen from the air so your organs can work. I…

The  blood circulatory system  ( cardiovascular system ) delivers nutrients and oxygen to all cells in the body. It consists of the heart and the  blood  vessels runni…

The  digestive system  ingests and digests food, absorbs released nutrients, and excretes food components that are indigestible. The six activities involved in this  p…

The neuron is the basic working unit of the brain, a specialized cell designed to transmit information to other nerve cells, muscle, or gland cells. Neurons are cells …

Natural barriers and the immune system defend the body against organisms that can cause infection. (See also Lines of Defense.) Natural barriers include the skin, mucous…

Green plants are the  protectors of biosphere . Save the from global warming. The main reason for global warming is the increase in the level of carbon dioxide in the …