In the 18th Century some scientists thought that the energy produced by the Sun was the result of chemical reactions. Which discovery would make this hypothesis doubtful? A) The Sun is made of gas

B) Heat is absorbed or released in chemical reactions.

C) Chemical reactions can take place at very high temperatures.

D) Energy is released when hydrogen nuclei fuse into helium nuctel.

Astone is thrown with a speed v0 and returns to earth, as the drawing shows. ignore friction and air resistance, and consider the initial and final locations of the stone. which one of the following correctly describes the change δpe in the gravitational potential energy and the change δke in the kinetic energy of the stone as it moves from its initial to its final location? options a.δpe = 0 j and δke = 0 j b.δpe is positive and δke is negative c.δpe = 0 j and δke is positive d.δpe is negative and δke is positive e.δpe = 0 j and δke is negative