Your answer is the Adrenal gland...Adrenaline
I think the correct answer is the first option. The key features of chordates would be notochord, dorsal tubular nerve cord, pharyngeal pouches, and a tail. These features appears in some period of their lives. They are deutorostomes where the anus would be formed first before the mouth.
Clues such as fossils such as bones, footprints, tar, etc, preserved underground helped inform scientists. You can also count how old a tree is when you cut it open and there are some alive for thousands of years so that is a possible way.
Answer:
A is the answer- away from the screen the lens needs to move
B. roots
i just took it and its the right answer