Questions

The US Congress consists of two bodies 

a) the Senate and   b) the House of Representatives. The Senate, composed of 100 members (two Senators from each State), is a powerful body and exercises a very real influence in national affairs.

A biosphere is the sum of all the ecosystems established on planet Earth.

An ecosystem is an area in which the plants and animals all interact to create a living environment. Therefore ecosystem is a smaller unit of earth, all ecosystems together form the earth.

A DVD is an example of Optical Disc.

Giraffe has the highest blood pressure among animals. 

This is due to the fact that there is a large pressure drop (~100 mmhg) as the blood is transported from the heart, up the neck, to the brain. This is about twice the normal blood pressure of humans (120/80 mmhg).