How does Earth's position relative to the Sun cause the four seasons?. Single choice. (1 Point)

A. Earth orbits the Sun once a year and is in different positions with respect to the Sun every three months, resulting in the four seasons.

B. The tilt of Earth's axis with respect to its orbit changes back and forth approximately 46 degrees every six months.

C. Earth's axis is tilted with respect to its orbit, so, as it revolves around the Sun its tilt with respect to the Sun changes, resulting in the four seasons.

D. Earth rotates on its axis every 24 hours, and since the axis is tilted with respect to the Sun, different parts of the Earth experience different day-lengths, resulting in the four seasons.

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

Lem 2 the data below are for the system ethyl propyl ether (1)-chloroform (2) at 0.5 bar. use the data to answer the following questions (all questions refer to p d 0: 5 bar). a) what are the boiling points of the pure components at 0.5 bar? b) a mixture with the overall composition z1 d 0: 1 is brought to 47.6ä±c, 0.5 bar. what is the phase? c) 100 mole of a mixture with z1 d 0: 1 (state a) is mixed with 22 mole of pure ethyl propyl ether vapor (state b). the mixing takes place at 47.6 ä±c, 0.5. bar. what is the phase of the resulting mixture (state c)? if the state is a v/l mixture report the number of moles and mole fractions in each phase. d) plot the txy graph and show states a, b and c. the graph must be done by computer and should be properly annotated. ethyl propyl ether (1) - chloroform (2) at 0.5 bar t ( ä±c) x1 y1 t ( ä±c) x1 y1 42.9 0.000 0.000 49.0 0.470 0.455 43.0 0.020 0.010 49.1 0.520 0.520 43.9 0.065 0.029 48.9 0.567 0.592 45.4 0.156 0.089 48.3 0.652 0.720 46.4 0.215 0.142 47.6 0.745 0.815 47.6 0.296 0.223 46.7 0.822 0.872 48.3 0.362 0.302 45.7 0.907 0.937 48.7 0.410 0.375 44.6 1.000

Chemistry worksheet - i am not sure what they are asking for exactly?