Question

what exactly are tides and what causes them, and why do they hate sandcastles so much? before we can figure out what is going on with the movement of the ocean, we need to take a look at a force that is always at work here on earth and even out in space, ________. gravity is the attractive force between all objects that have ____ and gravity is the force that creates tides.

Explanation:

The first blank refers to the force introduced right after, which is gravity. The second blank fills in the key property that objects must have to exert or be affected by gravitational force, which is mass.

Answer:

First blank: gravity
Second blank: mass