Two students make the following claims regarding the components of the solar system. • Student 1: The components of the solar system were formed from a spinning nebular
cloud containing dust, hydrogen, helium, and other gases that condensed under the
influence of gravity.
Student 2: The components of the solar system were likely to have been formed at the
same time as the formation of the universe the universe.

Match the following terms describing electrical events with the correct phases of the cardiac cycle. the ventricular muscle cells depolarize at the start of this phase. during this phase, na+ entry through the funny channels causes the pacemaker potential of sa nodal cells to gradually become less negative until it reaches threshold. the ventricular muscle cells repolarize right before this phase. the cytosolic concentration of calcium in the contractile cells of the ventricle is highest during this phase. a. isovolumetric relaxation b. ventricular ejection c. isovolumetric contraction d. ventricular filling

Suggest why placing wheels under a heavy box reduces the neccessary force required to push it along at a constant speed.

In the diagram below, the northern hemisphere would be in what season at position a a. fall b. winter c. summer d. spring