The evidence that scientists currently have suggests that life on earth a. began in the water b. first evolved around 3,500 million years ago c. began as single-celled organisms d. a and b e. all of the above

Galaxy whose shape seems different follow no set pattern are classified as

What kind of seafood would you expect to have the highest levels of mercury and why? kelp, because they use the sun to photosynthesize on the bottom trophic level. oysters, because they filter feed on plankton on a lower trophic level. small fish, because they eat plankton on a higher trophic level. sharks, because they feed on organisms on a higher trophic level.

How can you approximate the number of calories required to keep you in energy balance?