!PLEASE HELP ASAP! ASSIGNMENT IS DUE SOON! what mass of the radioactive isotope will be left after three(3) half-lives?

Environmental differences within ecosystems are generally caused by

Where substance is produced during cellular respiration

Which scientific design has both practical limitations and limitations due to scale? studying the effect of bleach on the growth of mold spores exposing cultures of duckweed to different intensities of light observing the replication of dna molecules with a hand lens using colored marbles to model a cross between two colors of rabbits