If the seawater carbonate ion (co3 2-) concentration is 270 µmol/kg, a) what is the approximate rate of calcification, and b) approximately how many days would it take 1 square meter of reef to accumulate 30 mmol of calcium carbonate (caco3)?

Which conditions are necessary for natural selection to occur? select all of the answers that apply. a. inheritable adaptations vary among individuals. b. the population size is increasing. c. more individuals are born than can survive. d. fitness varies among individuals. e. the environment changes suddenly and drastically.

Iwill make you brainliest pleeze answer this fast i have to turn it in really soon brainliest promise easy question 6th grade ! a weather map shows a high pressure system with circles around it. what does this mean? a) an occluded front b) areas of equal altitude c) areas of equal pressure d) a stationary front

Which of the following happened during the precambrian era? the first prokaryotic cells the first eukaryotic cells development of photosynthesis all of the above