Explanation

The human heart is an organ that pumps blood throughout the body via the circulatory system, supplying oxygen and nutrients to the tissues and removing carbon dioxide and other wastes. 

Explanation

Cholesterol is a waxy substance called a lipoprotein

Explanation

Explanation

Cigarette smoke and radon are two of the most common indoor hazards.

Most people spend upward of 90% of their time indoors. Without proper ventilation, many pollutants can accumulate indoors.

Explanation

Explanation

Comets are cosmic snowballs of frozen gases, rock and dust that orbit the Sun. 

When a comet's orbit brings it close to the Sun, it heats up and spews dust and gases into a giant glowing head larger than most planets.

Explanation

Human brain is divided into 3 parts.

01. Fore Brain

02. Middle Brain

03. Hin Brain

Explanation

The eye is made up of three coats, which enclose the optically clear aqueous humour, lens, and vitreous body. The outermost coat consists of the cornea and the sclera; the middle coat contains the main blood supply to the eye and consists, from the back forward, of the choroid, the ciliary body, and the iris.

Explanation

Gigantic clouds of dust and gas in space are called nebulae

Primarily hydrogen and helium, plus dust (silicates, carbon, ice). 

Occupying the space between stars and acting as a nursery for new stars

Explanation

The effects of the thyroid come from two iodine containing-hormones