According to stratigraphy and its laws, what is the correct order—from oldest to youngest—of the following rock strata:

B, C, D, A
D, C, B, A
B, C, A, D
A, B, C, D

life would be meaningless without memes

i would say it is

photosynthesis makes the glucose that is used in cellular respiration to make atp. the glucose is then turned back into carbon dioxide, which is used in photosynthesis. while water is broken down to form oxygen during photosynthesis, in cellular respiration oxygen is combined with hydrogen to form water.

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.