Based on fossil evidence, about how long ago did the first single-celled life form appear on Earth? 130 million years ago 1.5 billion years ago 2.5 billion years ago 4.1 billion years ago

Calvin ate a candy bar, which caused his body's blood glucose levels to become unbalanced. his body responded by initiating a feedback mechanism to return his body to homeostasis. place the steps of this feedback mechanism in order, starting with the blood glucose imbalance that occurred after calvin consumed the candy bar. a) calvin's blood glucose levels decreased. b) calvin's pancreas stopped secreting insulin. c) calvin's body cells started to take up glucose and store it as glycogen. d) calvin's blood glucose levels increased. e) calvin's pancreas started secreting insulin.

Variety of living organisms; includes genetic, species, and ecological types.

Waianapanapa beach in hawaii is a black-sand beach that was formed by waves crashing against volcanic rock. the sand can be very hot on sunny days. which statement best explains why? o a. the black sand has no heat capacity. b. the black sand absorbs no radiation. o c. the black sand is immune to insolation. d. the black sand has a low albedo.