1) This is a definition.
2) Protons are given by the bottom number (since atomic number = number of protons).
3) Neutrons = (mass number)-(atomic number), which are the top and bottom numbers, respectively.
4) Nuclear fusion involves combining two things together, which is only reflected by the last option.
5) This is a fact.
6) This is a fact.
7) This is a fact.
8) This is a fact.
9) The correct option is the explanation.
Answer : The time passed in years is 
Explanation :
Half-life = 5730 years
First we have to calculate the rate constant, we use the formula :
Now we have to calculate the time passed.
Expression for rate law for first order kinetics is given by:
where,
k = rate constant = 
t = time passed by the sample = ?
a = let initial amount of the reactant = X g
a - x = amount left after decay process = 
Now put all the given values in above equation, we get
Therefore, the time passed in years is
The sun makes the moisture go into the air and evaporate
Explanation:
A chemical reaction is one in which a chemical change occurs.
During a chemical change;
- The process is irreversible
- New kinds of matter produced
- There is a change in mass
Based on these premise;
Baking cake batter is a chemical reaction because you cannot reverse the process
Shredding a paper is not a chemical reaction because no new kind of matter is produced.
Twisting of a metal wire is not a chemical reaction
Yellowing of newspaper in sunlight is a chemical change. The process cannot be reversed
The crust of the Earth is thickest beneath the continents.
