Help please it’s due in 3 minutes

I think its the first one

Explanation:

A

Explanation:

Both students are Pushing/Pulling towards the same direction meaning if enough force is applied the object will move into that direction

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

it's c. elements are placed in rows based on how may valencies electrons have.