1. Which of these is an example of chemical weathering?
O Plants wedge their roots into cracks in rock and push it apart.
O Acid rainwater seeps into the ground and dissolves limestone.
O Gravitational force pulls rocks to the bottom of a mountain.
Rock pieces carried by river water wear away pieces of rock in the riverbed.

it always confuses me when i see it

explanation:

the fossil record extends back to a dog-like ancestor some 55 million years ago, which gave rise to the first horse-like species 55 to 42 million years ago in the genus eohippus.

measuring light intensity

light meters can be used to measure light intensity. the meter is held at the soil surface and pointed in the direction of the maximum light intensity, and then the meter is read.

errors can be made when measuring light intensity by accidentally shading the light meter. the reliability of the results can be checked by taking many samples.