For part of our orbit the northern half of Earth is tilted toward the Sun. This is summer in the northern hemisphere; there are longer periods of daylight, the Sun is higher in the sky, and the Sun's rays strike the surface more directly, giving us warmer temperatures.
The answer is C. They lower the activation energy of an elementary step of a reaction
This makes the reaction rate to increase since less energy is required to make a reaction occur.
Cover with metal .Any elements other than hydrozen and helium concentration shows an absorbance
Delete the cactus and the tree on the right for the first one and the third picture delete the lion moose Buffalo