Flood prevention

This task is about adding words to a text so that it makes sense.
 
forest
 
The following piece of writing has some spaces where words are missing.
 
First, read the whole piece of writing through to get an idea of what it is about. Then fill each space with ONE word so that the whole piece of writing makes sense. You are able to change answers as you go.

When you have filled in all the spaces, re-read the text to check that the whole piece of writing makes sense.

Question 1Change answer

Flood prevention
 
Forests are of vital importance in preventing floods and erosion. Rain falls gently on land densely 1 with large trees because the trees' 2 help break the force of the 3 before it hits the ground.
 
Roots, 4 leaves and twigs beneath the trees 5 a soft bed that absorbs the 6 like a giant sponge. Some of 7 water runs off gradually, finding its 8 to springs and streams. But when 9 falls on bare earth, it strikes 10 great force and runs off swiftly, 11 the fertile top soil along with 12. Then the water fills up the 13 and rivers too fast for their 14 to hold it all. Costly, tragic 15 are often the result.