Will give a brainlest grasses can withstand the fires common to grasslands because grasses are full of moisture store water in their leaves grow thickly together have extensive root systems

The answer is;  have extensive root systems

Most grasses have ‘runner’ roots which are stems of the plant that grow horizontally below the soil surface. The buds on the stem are what gro to the leaves that emerge from the soil surface and we see as grass blades. Adventitious roots also grow downwards from this stem. Wildfires are not able to  reach the stem and roots under the soil surface so grass can easily regrow even if the blades are destroyed.  

genetic variation will increase because of a new habitat and food source.

explanation: