Lava slowly filled _________ that were created by impacts of massive asteroids more than three billion years ago.
tunnels
holes
basins
bowls
_________ occurs in rivers when rocks are worn away by the moving water.
Erosion
Mud
Irritation
Settling
The metal gate __________ the cars from entering the parking lot.
broke
turned
allowed
prevented
That is ____________ ink, so the stain will never go away.
tough
permanent
dry
blue
Thick layers of _________ can build up in rivers and lakes.
sediment
fish
mud
water
A man at the store ________________ how to use the sharp knives that were for sale.
tested
told
copied
demonstrated
The healthy tree withered and ___________ because bugs had eaten away the bark.
deteriorated
died
stretched
fell down
We hiked up the mountain and walked along the cold ice of the _________.
island
refrigerator
ground
glacier
This ice __________ was created by years of water dripping down and freezing.
formation
icicle
sculpture
house
___________ can turn large mountains into small hills over time.
Bacteria
Sandpaper
Friction
Weathering