Scientists have studied the fossilized shells of prehistoric, single-celled marine organisms. some of these shells were thin, which indicates that the organisms lived in very warm ocean water. such evidence indicates that the climate during this time may have been a) moderate b) arctic. c) tropical. d) the same as it is today.

Ablastocyst is a group of cells that forms after a human egg is fertilized. the blastocyst consists of two types of cells. some of these cells will become the placenta. what do the other cells develop into?

Darrel conducted an experiment with the following procedure: fill two cups with ice water. place an uninflated balloon snuggly onto your left index finger. blow a little air into an identical balloon, and place it onto your right index finger. place both fingers into the cups of ice water. darrel noticed that his right finger felt warmer in the ice water than did his left finger. which of the following does the experiment show? a. air is a good radiator of heat. b. air is a good insulator of heat. c. air is a good conductor of heat. d. air is a good convector of heat.

Advances in technology have enabled scientists and researchers to better study the evolutionary relationships between species