In the reactants there is a curvy arrow, what does
the direction of the arrow indicate?
because cations are sharp and anions are
dull
because the anions and cations share
electrons
because the cations give away an electron
and the anions accept electrons

Cis the

The density of water is 1 g/cm cubed and in order for the pebble to sink its density has to be greater than the density of water and in order for the twig to float its density has to be less than the density of water

There is no reason to think the results are biased or not conducted properly but you should not assume the results are correct just because they were done in a laboratory so the answer would be c. it is likely to be reliable because the results support the conclusion presented.