Explanation

The element required for solar energy conversion is silicon: 

Silicon is the most common semiconductor material: Silicon is used in about 95% of solar cells sold today. 

Silicon is a naturally occurring element: Silicon is the second most abundant element on Earth, after oxygen

Explanation

"The branch of biology that deals with organisms living in the ocean is called marine biology."
:
The term Marine Biology is used to refer to the study of marine organisms and ecosystems.

Explanation

A sphygmomanometer measures blood pressure in the brachial artery, which is the main artery that supplies blood to the muscles in the upper arm and elbow. 

Explanation

​​The word geology means 'Study of the Earth'.

Also known as geoscience or earth science,

Geology is the primary Earth science and looks at how the earth formed its structure and composition,

and the types of processes acting on it.

Explanation

The force the earth attracts a body towards itself is called weight.

It is not constant but varies from place to place due to changes in the value of g

 Since it is a force, its SI unit is also Newton (N).