Eyes and ears are the sense organs of human beings.

The proverb “Closed eyes open up ears” tells about the importance of our ears when eyes are closed.

Ear is a sense organ of hearing. Human beings have two ears. Ears help us to hear different sounds and discriminate against them. It is an important organ for humans. We should also protect our ears from pointed objects, loud sounds, etc.

Explanation:

Human beings have five sense organs- Eyes, Ears, Nose, Skin and Tongue.

An eye is the organ of vision. Through eyes we can see the world, differentiate our surroundings depending on its shape, size, color, length, breadth, height, distance, etc.

Because of eyes we gain knowledge about our surroundings. Eyes are important to us and we should protect our eyes.  

An ear is the organ of hearing. We can hear different sounds and differentiate them because of our ears. We should also protect our ears from hearing loss.

When we close our eyes, we cannot see anything, but we can hear different sounds because of our ears. Ears receive sound through the pinna (outer part of ear) and direct them into ear`. The sounds pass through the inner part of ears and reach the brain that recognizes sound. Ears are important for hearing.

yes they are one of the key sense organ

explanation:

the largest database of organic compounds lists about 10 million substances, which include compounds originating from living organisms and those synthesized by chemists. the number of potential organic compounds has been estimated at 1060—an astronomically high number. the existence of so many organic molecules is a consequence of the ability of carbon atoms to form up to four strong bonds to other carbon atoms, resulting in chains and rings of many different sizes, shapes, and complexities. the simplest organic compounds contain only the elements carbon and hydrogen, and are called hydrocarbons. even though they are composed of only two types of atoms, there is a wide variety of hydrocarbons because they may consist of varying lengths of chains, branched chains, and rings of carbon atoms, or combinations of these structures. in addition, hydrocarbons may differ in the types of carbon-carbon bonds present in their molecules. many hydrocarbons are found in plants, animals, and their fossils; other hydrocarbons have been prepared in the laboratory. we use hydrocarbons every day, mainly as fuels, such as natural gas, acetylene, propane, butane, and the principal components of gasoline, diesel fuel, and heating oil. the familiar plastics polyethylene, polypropylene, and polystyrene are also hydrocarbons. we can distinguish several types of hydrocarbons by differences in the bonding between carbon atoms. this leads to differences in geometries and in the hybridization of the carbon orbitals.

that's what i got you can count the number of atoms