What are the two sources of heat in the earth's interior? a. leftover heat from formation and radioactive decay b. magma and liquid outer core c. radioactive decay and convection currents d. sunlight and meteor impacts

The answer is; A

Since the earth was formed approximately 4.6 billion years ago, the heat that was generated during its formation has not been entirely lost. Some of the heat is still insulated inside the earth (below the crust) and is only lost very slowly over time. In addition, the earth hardly cools because the lost heat is replenished by the heat from radioactive elements that decay  in the earth’s core. Some of these radioactive elements are uranium.  

stimulus is a change in the environment that causes an organism to react. the response is the reaction to the stimulus. some examples of stimuli for zebras are drought, to many predators, and bad feeding grounds such as dead grass or plants. zebras respond to stimuli just like all other living organisms

yes

no

blue is scattered more than other colors because it travels as shorter, smaller waves. this is why we see a blue sky most of the time.