Questions

True, the greenhouse effect is caused solely by human activities such as deforrestation, depletion of natural resources and emission of CO2 by using vehicles, refrigerators and AC's.

Nitrogen (N2) forms Three Covalent Bonds to become stable.

Here the Atmomic Number of Nitrogen is 7. Because there are 2 electrons in the first orbital and 5 in the second and you still have space for 3 more. So it shares, 3 to get the stable octet. Therefore, there are 3 covalent bonds in N2.

An autoimmune disease is a condition in which your immune system mistakenly attacks your body.

The immune system normally guards against germs like bacteria and viruses. When it senses these foreign invaders, it sends out an army of fighter cells to attack them. Normally, the immune system can tell the difference between foreign cells and your own cells.

In an autoimmune disease, the immune system mistakes part of your body — like your joints or skin — as foreign. It releases proteins called autoantibodies that attack healthy cells. Some autoimmune diseases target only one organ. Type 1 diabetes damages the pancreas. Other diseases, like lupus, affect the whole body.

Hence, Systematic lupus erythematosus is an autoimmune disease that affects multiple organs.

the powerful cell phones can transmit a signal of 3 watts.

humming Bird is the smallest among all the birds

Former India captain Mahendra Singh Dhoni became the first wicketkeeper in world cricket to effect 100 stumpings in One Day Internationals. He broke the record of former Sri Lankan captain Kumar Sangakkara.

Associated Press (AP) is world's oldest news agency followed by Reuters and Agence France - Presse.