The answer is A because limestones are mostly calcium carbonate. When acidic rainwater falls on limestone a chemical reaction happens. These dissolve in the water, and then are washed away, weathering the rock.
A solution isn´t a pure substance.
a.solution
solution: a homogeneous molecular mixture of 2 or more substances.
Example of solutions: H2O +NaCl.; wine+ water, milk + water.
Genes are made of DNA and are carried on chromosomes.
Answer:
Electrons and protons are not positively charged
Explanation:
Neutrons are the only ones positively charged in the structure of an atom.... Also like charges repel which means a -ive and a - ive will repel when together