Answer:
A
Explanation:
because B is wrong as it doesn't have the same mass number. C is wrong as it has different number of neutrons. D is wrong as it has more neutrons than protons.
Answer:
The Law of Definite Proportions ensures that chemical compounds are always created using the same proportions, regardless of the amount of the compound which is being made
Answer:
it's natural selection
Explanation:
adaptation is when you adapt to some situation
Explanation:
A chemical reaction equation that contains same number of atoms on both reactant and product side is known as a balanced chemical reaction equation.
For example, 
Here, number of reactant molecules are as follows.
Na = 2
S = 2
Cd = 1
O = 4
Number of product molecules are as follows.
Na = 2
S = 2
Cd = 1
O = 4
As there are already equal number of atoms on both reactant and product side. Hence, the reaction equation is balanced.
Also, in this reaction both
and
are present as aqueous solution. And, CdS is the precipitate that is formed as it is the insoluble solid that forms.
is present in aqueous state.