Balance the following:
Reactants Products
B2+ _W2->BW3

B2 + 3W2 ---> 2BW3

Explanation:

You have 2 B on the right and 1 B on the left to balance out B, you need to add 2 wich gives you 6 W on the left and 2 W on the right. To baance W on both sides you add a 3 to the W on the right which gives you 6  W on both sides.

geosphere and hydrosphere.

this is because the geosphere has to do with geological events, while the hydrosphere controls all water on earth.