General Science Questions

A rotating column of air is called as a Tornado which extends from the thunderstorm to the ground.

In transfusions of packed red blood cells, individuals with type O Rh D negative blood are often called universal donors. Those with type AB Rh D positive blood are called universal recipients.

The immune system of a person with AB blood will accept blood from all possible donors, whether they have O, A, B, or AB blood. Since both A and B antigens are present in a person with AB blood, the recipient won't reject the blood. The body identifies that blood as "self" rather than "foreign."

Horography is an art of constructing watches or dials for measurement of time.

Primary productivity refers to plants that make their own food using sunlight, water and availability of nutrients. Hence, they are not limited by time.