How many plant and animal species do wildlife experts estimate are endangered

Hydroelectric uses moving water to do work such as grinding grains in a mill true or false

Which u.s. state lists the horned toad as its state reptile?

Fossils of ancestors of the modern horses show a small 4-toed almost dog-like browsing animal named eohippus over time the horses got larger lost toes and changed to a grazing diet what is the best explanation of why this change occurred