After three half-lives, a sample contains 20 grams of parent isotopes. how many grams of the parent isotope were present to start?

i believe it is c: genes for body color and wing size are inherited separately from each parent.

the answer is c a tornado

above statement is not a true statement about the open ocean because the open ocean has low levels of nutrients. most of the photosynthetic activity on earth occurs in the open ocean within the photic zone. organisms in the deep ocean are exposed to frigid temperatures and total darkness but it does not begin at the low-tide mark.