Answer:
Option D which is Sn4- is the answer
Explanation:
Because when two equal forces are applied from opposite directions, they "eliminate" each other.
The train would go right if a 3N force was only applied in the right direction, and it would go left if the same force was only applied to the left.
If a 3N force was applied to the right and a 2N force to the left, it would equal a 1N force to the right (3-2=1).
But there it's 3-3=0, so in practice the force is 0N. Therefore the train won't move.
I think the best answer that will describe chemical change is the first option. During a chemical change, b<span>oth the identity and the properties of a substance change because new substances are being formed by a chemical reaction. An example is rusting of steel</span>
Answer is B. Releases heat and is exothermic
