A Multi-Celled organism has many cells (more than one). Examples would be plants, humans and animals/mammals.
A Single-Celled organism only has one cell that makes up it's entire self. Examples would be bacteria and archaea.
I'm assuming you mean the molecular compound

and it's name is Hydronium. Hope this helps :)
Complementary mRNA strand would be the following:
AUCAUCAUC.
3 Repeating codons of AUC, on the mRNA strand.
DNA stands for Deoxyribonucleic acid which means it is a nucleic acid. RNA stands for Ribonucleicacid. RNA produces proteins
DNA replicates and stores genetic information.
RNA converts the genetic information contained within DNA to a format used to build proteins.
I would have to say the answer is A based off the information above.
Please correct me if I'm wrong.
A group of tissue that work together is a organ