D: they have new dna combinations
Parantheses mean present of a subgroup or a group of polyatomic ions in a chemical reaction.
<u>Explanation:</u>
In a chemical reaction, sometimes, a compound may be composed of group of polyatomic ions with other ions. Some of the polyatomic ions are sulfate, carbonate, nitrate, hydroxide, bicarbonate, ammonia etc.
So these polyatomic ions are formed by combining two or more elements. Thus, if the number of polyatomic ions in a compound is more than one, then we use parathesis and write those polyatomic ions in it and write the number of polyatomic ions present in the compound as subscript of the parathesis.
For example, Fe₂(SO₄)₃
So here SO₄ is a polyatomic ion and in the compound 3 atoms of SO₄ is required to neutralize the compound and thus paranthesis is used. Thus, parantheses mean present of a subgroup or a group of polyatomic ions in a chemical reaction.
Answer:
The balance chemical equation can be given as:

Explanation:
When zinc sulfide is allowed to react with zinc sulfate it gives zinc metal and sulfur dioxide gas as a product.The balance chemical equation can be given as:

According to reaction we can see when 1 mol of zinc sulfide reacts with 1 mol of zinc sulfate it forms 2 moles of zinc metal and 2 moles of sulfur dioxide gas.
Answer:
Due to the known fact that certain animal ect lived on certain country/continents due to climate water type ect when fossils of various animal where found in unusual parts of the earth the theory came that all the continent where joined together due to fossil and rock types being found on continents in which would be impossible to reach if not joined together in the beginning
Explanation:
I
Answer:
i think it's D tbh, just cus it was the scientist who did the work