About how many years ago do scientists suggest that the earth cooled enough for water vapor to condense.
A)20 millions years
B)4.6 billion years
C)4.4 billion years
D) 5.5 billion years

answer; i believe the answer is (polygenic inheritance;

blue

light-years

magnitude

answer: accepted answer: aquatic animals use the oxygen dissolved in water to carry out respiration. since the amount of dissolved oxygen in water is low as compared to the amount of oxygen in the air, therefore the rate of breathing in aquatic animals is much faster than it is in terrestrial animals.

explanation: