a scientist finds a fossil that she thinks might make a good index fossil. which characteristic does this fossil most likely have?

for example, no new evidence will demonstrate that the earth does not orbit around the sun (heliocentric theory), or that living things are not made of cells (cell theory), that matter is not composed of atoms, or that the surface of the earth is not divided into solid plates that have moved over geological timescales .

i think the answer is composed of atoms

idk and i also need to know where are those bio brainy acts lol