Approximately what portion of north america is covered by forests?

1/4

1/3

1/2

3/5

Geologists know that potassium-40 decays to argon-40, with a half-life of 1.3 billion years. if an analysis of a feldspar crystal in a sample of granite shows that 75 percent of the potassium-40 atoms have decayed to form argon-40, what is the age of the granite

During which era in earth's history were the first insects? mesozoic precambrian cenozoic paleozoic

The body paragraphs in an informative essay should include clear examples. a thesis statement. restated evidence. a clear direction.