The answer is A because D is the most recent layer so it would go D,C,B,A
I believe the answer you are looking for is median.
example:
2 4 6 |8| 10 12 14
median: 8
three on each side of "8"
I think it is C as plants take in Co2 and release oxygen which humans use to breathe.
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Scientists believe that ancient ancestors of all animals were single celled eukaryotes that sometimes grew in colonies. The correct option among all the options that are given in the question is the second option or option "B".
The Cambrian Explosion resulted in the evolution of the first representatives of most animal phyla. The correct option among all the options that are given in the question is option "B".
B. ventricles
The chordae tendinae, also referred to as heart strings, are tendons that connect the atrioventricular (tricuspid) valves to the muscular wall of the heart. These chords are made predominantly of collagen, while the remaining part is elastin. They play the vital role of maintaining the structure of the valves they connect to. Due to the high pressure generated within the heart, it is entirely possible for the atrioventricular valves to turn inside out. The chordae tendinae prevent this from happening and keep the valves functioning properly.