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Review of Literature

Plants respond to directly to Earth's gravity and to light. Plant stems grow away from the Earth's core and its roots grow closer to Earth's core. The plant stems grow up to the light and its roots grow away from the light (Moreno). Gravitropism is plants response towards gravity and plants response to light is phototropism (Moreno). Gravitropism and photopism are both controlled by plant hormones. Roots change direction when a plant is tipped to the side, they also change direction when they collide into a dense object such as a rock or twigs. If a plant is upside down than the roots will curve upwards towards the light, and a normal plant grows upward.

Gravity is objects with mass attracted to each other. Gravity keeps Earth orbiting around the sun and it also keeps the moon orbiting around the Earth. The first known theory of gravity was thought of by Issac Newton by seeing an apple fall of a tree. The human body can handle increased g forces, this has been proved by many astronauts in their training exercises(Smith). Tides caused by the rotation of the Earth and the gravitational effects of the moon and sun (Smith). The highest known acceleration voluntarily experienced by a human is 46.2 g by g force pioneer John Stapp (Smith).

If you are going to start growing tomato seeds indoor for 6 to 8 weeks (Tomatoes). When you see the stem of the plant move it outside and start to grow it there. Select an area where it is full of sunlight and good soil and 6 hours of sunlight. Before transplanting the plant outside till the soil to about one foot and mix in fertilizer or manure. Plant each seed two feet apart from each other. Water well to reduce shock of roots and water about 2 inches of water per week (Tomatoes). Leave the tomatoes on the vine as long as possible and if they get to much sun they will crack (Tomatoes).

Three quarters of the Earth is covered in water leaving only one quarter of land. The human body is 60% water and Blood is 92 percent water, the brain and muscles are 75 percent water, and bones are about 22 percent water (Water Facts). A human can survive a month without food but can only survive a week without water. Only 1% of water is fresh water and is available for human consumption ( Water Facts ). **(Whitehead)**


 * Works Cited **

Moreno, Nancy P. "BioEd Online." //How Does Gravity Affect Root Growth? - //. N.p., n.d. Web. 25 Sept. 2013.
 * This website is created by teachers at the Baylor College of Medicine and is the center of educational outreach.

Smith, Rene. "Interesting Gravity Facts - Acceleration, G-Force, Mass, Formula, Law, Orbit." //Interesting Gravity Facts - Acceleration, G-Force, Mass, Formula, Law, Orbit //. N.p., n.d. Web. 25 Sept. 2013.
 * Website is created by someone who was studying the topic for four years at Canterbury University and knows what they are talking about.

"Tomatoes." //: Planting, Growing and Harvesting Tomato Plants//. The Old Farmer's Almanac, n.d. Web. 25 Sept. 2013.
 * The Old Farmer's Almanac was made a long time ago and was created by people who know a lot of plants and how you should grow them.

Whitehead, Bruce. "Water Facts." //Water Facts | The Water Information Program //. N.p., n.d. Web. 17 Oct. 2013.
 * This website is created by people who have researched a topic enough to write about.