What causes sunlight to strike at different angles at different times of the year

a. ecllips of the sun

b. tilt of earth

c. ratation of earth

d. apperance of the moon

Compare and contrast physical changes with chemical changes.

Explain the relationship between forward and backward reactions in equilibrium, and predict how changing the amount of a reactant (creating a tension) will affect that relationship.

Sally is making a model of a magnesium atom with an atomic mass number of 24 for her chemistry class. she has foam balls for the protons, neutrons, and electrons. she has added 6 neutrons to her model so far. how many more neutrons does she need to add to complete her neutral atom of magnesium?