There are many types of forces, but our answer choices include four types. In order to answer this question correctly, we need to be able to decipher between them.

Applied forceis a force that is applied by a person to an object.

Gravity forceis also known as the weight of the object. It's the force that allows a large object to attract another object towards itself.

Normal forceis also known as supportive force. It is the force exerted upon an object that is in contact with another object, one object holds the other up.

Friction force is the force exerted by a surface as an object tries to moves across the surface.

让我们想想问题的场景。What causes a person to be kept on the ground, rather than floating around? Gravity forces us towards the ground; thus, gravity force is the correct answer.

There are many types of forces, but our answer choices include four types. In order to answer this question correctly, we need to be able to decipher between them.

Applied forceis a force that is applied by a person to an object.

Gravity forceis also known as the weight of the object. It's the force that allows a large object to attract another object towards itself.

Normal forceis also known as supportive force. It is the force exerted upon an object that is in contact with another object, one object holds the other up.

Friction force is the force exerted by a surface as an object tries to moves across the surface.

让我们想想问题的场景。A plate is sitting on the table, they are in contact with one another and the table is keeping the plate from falling to the ground; thus, this is an example of normal force.

There are many types of forces, but our answer choices include four types. In order to answer this question correctly, we need to be able to decipher between them.

Applied forceis a force that is applied by a person to an object.

Gravity forceis also known as the weight of the object. It's the force that allows a large object to attract another object towards itself.

Normal forceis also known as supportive force. It is the force exerted upon an object that is in contact with another object, one object holds the other up.

Friction force is the force exerted by a surface as an object tries to moves across the surface.

让我们想想问题的场景。We have a marble, an object, that is rolling across the floor, which is a surface. Based on the definitions of the types of forces above, friction force is the correct answer.

There are many types of forces, but our answer choices include four types. In order to answer this question correctly, we need to be able to decipher between them.

Applied forceis a force that is applied by a person to an object.

Gravity forceis also known as the weight of the object. It's the force that allows a large object to attract another object towards itself.

Normal forceis also known as supportive force. It is the force exerted upon an object that is in contact with another object, one object holds the other up.

Friction force is the force exerted by a surface as an object tries to moves across the surface.

让我们想想问题的场景。We have a student pushing a desk, which is an object, across the room. The student would have to apply some force to get the desk to move. Looking at the types of forces above, applied force fits this scenario best.

Planet Earth is roughly

The Earth orbits the sun.

The moon orbits the Earth.

Renewable energy sources are sources of energy that are naturally replaced or energy sources that won't run out.

Wind is the only example of an energy source that won't run out and is the correct answer.

Natural Selection is the process that enables organisms that are best suited for the environment to live and pass on their genetic traits.

突变的特点是作为一个错误或更改in an organism's DNA.