Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| ENERGY Form of engery |  | EVENT Abstract description of event involving energy |  | ENERGY SOURCE | CONDITION A condition that must be satisfied |  | CONSEQUENCE The result of the energy source, given the condition |
| --- | --- | --- | --- | --- | --- | --- | --- |
| a magnetic field | can | attract iron | ; for example, if | a permanent magnet | is near a steel nail | then | the nail will move towards the magnet |
| electrical energy | can | be changed to sound energy | ; for example, if | an electrical signal | enters the speaker of a telephone | then | the speaker will convert the electrical signals into speech |
| electrical energy | can | produce light and sound | ; for example, if | a bolt of lightning | strikes a tree | then | there will be a bright flash and a loud noise |
| electricity | can | be converted to light | ; for example, if | a battery | is connected with wires to a light bulb | then | the bulb will glow with light |
| friction | can | cause heat | ; for example, if | a speeding car | skids its tires on a road | then | the skidding will cause the tires to become hot |
| friction | can | slow an object moving along a surface | ; for example, if | a rolling ball | is moving on flat ground | then | the ball will slow and eventually halt |
| friction | can | slow an object moving along a surface | ; for example, if | a rolling ball | is rolling through thick grass | then | the ball will slow and quickly come to a halt |
| gravity | can | pull one object towards another | ; for example, if | a person | throws a ball up into the air | then | the Earth will pull the ball back down |
| gravity | can | pull an object downwards | ; for example, if | a marble | is dropped into a glass of water | then | the marble will fall to the bottom of the glass |
| gravity | can | pull an object downwards | ; for example, if | a ball | is released in the air with no support | then | the ball will fall to the ground |
| gravity | can | pull an object downwards | ; for example, if | a rock | is released at the top of a hill | then | the rock will roll down the hill |
| heat energy | can | be transferred from one location to another | ; for example, if | a stove | heats a kettle of water | then | the heat will move from the stove to the water |
| heat energy | can | be changed to sound energy | ; for example, if | a kettle with a whistle | is used to boil water | then | the kettle will make a whistling sound as the steam from the boiling water escapes from the kettle's spout |
| high friction | can | cause an object to move slow | ; for example, if | a bicycle | is moving on a rough road | then | the bicycle will move slowly |
| light | can | cause heat | ; for example, if | bright sunlight | shines on asphalt | then | the asphalt will become hot |
| light energy | can | be reflected by an object | ; for example, if | a flashlight | shines on a mirror | then | the light from the flashlight will bounce off the mirror |
| light energy | can | be changed to sound energy | ; for example, if | a radio wave | is received by a radio | then | the radio will convert the radio wave into sound |
| low friction | can | allow an object to move fast | ; for example, if | a bicycle | is moving on a smooth road | then | the bicycle will move fast |
| magnetic energy | can | produce motion | ; for example, if | a compass needle | is allowed to rotate freely | then | the compass needle will turn until it points north |
| magnetism | can | cause motion | ; for example, if | a magnet | is waved near a pile of steel nails | then | the nails will move |
| magnetism | can | attract iron | ; for example, if | a magnet | is moved towards a pile of iron nails | then | the nails will move as the magnet comes closer |
| mechanical energy | can | be converted to sound energy | ; for example, if | a pianist | strikes a piano key | then | the piano will make a musical sound |
| mechanical energy | can | be used to move something from on location to another | ; for example, if | a worker | applies a shovel to a pile of dirt | then | the dirt will move |
| mechanical energy | can | be used to move something from on location to another | ; for example, if | a baseball player | throws a baseball | then | the baseball will move away from the player |
| mechanical energy | can | be changed to sound energy | ; for example, if | a baby | shakes a rattle | then | the rattle will make a noise |
| mechanical energy | can | produce motion | ; for example, if | a person | pushes a wooden block on a floor | then | the block will move across the floor |
| motion of a liquid against a solid | can | cause erosion of the solid | ; for example, if | the ocean's waves | are pounding against the coast | then | the waves will wash away some of the coastal soil |
| sound | can | cause vibration | ; for example, if | a lound sound | occurs near a wooden door | then | the door will vibrate |
| sound energy | can | move through air | ; for example, if | two people | are having a converstation at a table | then | sound is moving through the air between them |
Question:
"When a person throws a ball in the air and it falls back to Earth, that is an example of what pulling it back down?" Select the correct choice to answer the question or fill in the blank.
Choices:
(A) Electrical energy
(B) Magnetism
(C) Sound energy
(D) Gravity
Answer:
(D) Gravity