The source of energy that keeps the Sun shining today is ________.
A) gravitational contraction B) nuclear fusion
C) chemical reactions D) nuclear fission
Question 2
The number of confirmed extrasolar planets
A) is about 600, and is not expected to rise very much.
B) is about 800, and is rising slowly, as observations are quite difficult.
C) was about 800 at the time of publication but is rising rapidly due to new observations by the Kepler spacecraft.
D) has been decreasing as some observations thought to be planets have been disproven.
E) is zero; there are observations thought to be of extrasolar planets but none has yet been confirmed.
Premature ventricular contraction.
Environmental Energy Flow
Examples of USP labels Source: Courtesy of Novartis Pharmaceuticals Corporation and Mallinckrodt Pha
Calcium channels and muscle contraction: (a) Calcium channels open as the action potential travels ...
Cover heat source to slow cooling by placing a towel over it.
Mixed dishes such as hamburgers and pizza are a major source of solid fats in the diets of Americans