RNA (Ribonucleic Acid) is a polymer, which is a large molecule made up of smaller repeating units. In the case of RNA, the repeating units are nucleotides. These nucleotides, being the subunits of a polymer, are called monomers. Picture it like a necklace, where the string is the RNA and the beads are the nucleotides. Now, the RNA necklace can have unlimited beads, or nucleotides.

But how are these nucleotide 'beads' attached to the RNA 'string'? This is where we bring in the concept of a condensation reaction. A condensation reaction is like a molecular game of "merge and lose." When two molecules decide they want to join forces, they also lose a small part of themselves in the process - in this case, water (H₂O).

In the scenario of RNA, the condensation reaction occurs between a hydroxyl group (OH) on the phosphate of one nucleotide and another hydroxyl group on the pentose sugar of the second nucleotide. It's like two hands with a finger each extended, ready for a firm shake. But, in shaking hands, they also need to drop the water bottle they were each partially holding (the H from one OH and the OH from another).

The fun part is that even though they lose water, they form a bond. The remaining oxygen from the hydroxyl group (the one that dropped its 'H') forms a new covalent bond with the second nucleotide. You can imagine it as if they tied a strong knot while shaking hands, ensuring they stay connected.