Question

Objective for eco friendly or eco frenzy

Answer 1

Being eco-friendly or environmentallyfriendly is becoming more and moreimportant. ... Eco-friendly products promote green living that help to conserve energy and also prevent air, water and noise pollution. They prove to be boon for the environment and also prevent human health from deterioration.

Answer 2

Echo:

When a sound wave is produced in air, some of it is absorbed after hitting with a reflector while some of the sound wave is reflected back to the listener. This reflected sound is called echo.

Applications of Echo:

1. Since bats cannot see from their eyes, so they use the technique of echolocation to locate their ways. Bats can understand from the reflected sound if there is any object before it. It hunts its prey by using this technique.

2. This technique is also used to find the depth of sea or distance of submarines.

3. It also helps to estimate the distance or hills and mountains.

4. This technique is also very helpful in the medical field as well. Doctors used this phenomenon in cardiograph, sonogram and many other medical diagnosis. 

Hope it will help you. Thanks.