Question Video: Selecting the Statement about Gravity That Is Not True | Nagwa Question Video: Selecting the Statement about Gravity That Is Not True | Nagwa

# Question Video: Selecting the Statement about Gravity That Is Not True Science • First Year of Preparatory School

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Which of the following is not true about the function of gravity? [A] It keeps the hydrosphere’s position on Earth. [B] It keeps objects and organisms on Earth’s surface. [C] It is important for the stability of living organisms when moving. [D] It has no effect on the atmosphere.

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### Video Transcript

Which of the following is not true about the function of gravity? (A) It keeps the hydrosphere’s position on Earth. (B) It keeps objects and organisms on Earth’s surface. (C) It is important for the stability of living organisms when moving. (D) It has no effect on the atmosphere.

The question mentions gravity. Gravity is a force which attracts or pulls objects towards the center of the Earth. Everything on Earth which has mass is pulled towards the center of the Earth. If we think about all the things on Earth which are pulled by gravity, we must first think of all the things that have mass. Do land, soil, and rocks have mass? Yes, gravity acts on these. What about the seas, lakes, and rivers? Yes, all water bodies have mass. We call all the water bodies on Earth, as well as water under the ground and in the atmosphere, the hydrosphere. The hydrosphere is the total amount of water on a planet, including water on the surface, under the ground, and in the air.

Gravity holds seas, oceans, and rivers in place. It also holds water in the air from floating off into space. Statement (A), it keeps the hydrosphere’s position on Earth, is true. We can rule out this answer as we are asked for the statement which is not true.

All living organisms have mass. Gravity also pulls on all living organisms and keeps them and us from drifting off into space. Also, all nonliving objects have mass and are held by gravity. So statement (B) is true. It keeps objects and organisms on Earth’s surface.

Not only that, but the bodies of all organisms function best under the influence of the gravity of our planet. For example, our muscles have sufficient strength to move our bodies even though gravity pulls us towards the Earth every day. If there was no gravity, we could not run, walk, or move normally. We need gravity to use our bodies as we do. We can rule out answer (C). It is important for the stability of living organisms when moving. This statement is true.

What about air, the atmosphere? Air does have mass. The particles are just very far apart, so air feels light. The atmosphere is the layer of gases or the air that surrounds the Earth. These gases are necessary for all life. The atmosphere is made from gases such as nitrogen gas, oxygen gas, carbon dioxide gas, water vapor, and small amounts of other gases. If the Earth did not have gravity, gas particles in the air would just float away into space. Organisms would not survive without these gases and the atmosphere. But gravity pulls on the atmosphere and holds it to the Earth. Since gravity does have an effect on the atmosphere, we can see that statement (D), it has no effect on the atmosphere, is incorrect.

We were asked to select the statement which is not true. So statement (D), it has no effect on the atmosphere, is the correct answer.

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