What event is thought to have occurred about 3.5 billion years ago?

A. The first Eukaryotic cells appeared
B. Earth formed from cosmic bodies and debris combining
C. Earth cooled enough for liquid water to exist
D. The first prokaryotic cells appeared

Guinea pig coat color is determined by a single gene. the allele for black coat color is dominant to brown. in a cross between twoblack-haired guinea pigs, 20 offspring are born. if both parents were heterozygous, probability would predict that approximately howmany of the 20 offspring would have brown hair?

Why did adult crab numbers decline in he ecosystem, even though sea stars were still available?

2. cheryl hears a new song on the radio every day during the week on her commute to work. surprisingly, when the song comes on at a party on saturday night, she knows most of the words without trying. describe the three ways that we use cognition to learn without reinforcement. which type of cognitive learning without reinforcement best explains how cheryl knew the song lyrics? explain your answer.