Question

A student is studying a rock formation. Which two questions could the student answer to determine if the rocks underwent chemical weathering?


Do the rocks have reddish-brown spots?


Do the rocks have small holes all over their surface?


Do the rocks experience extreme heating and cooling?


Do the rocks have cracks where plants are growing from?


Do the rocks have cracks where water can freeze and thaw?

Answer 1

- Do the rocks have reddish-brown spots? (Yes — indicates oxidation, a chemical change.)
- Do the rocks have small holes all over their surface? (Yes — can indicate dissolution or chemical breakdown of minerals.)

The other choices describe physical weathering (thermal stress, root wedging, freeze–thaw).