The anwer is DNA to your question
Thick rigid cell wall is not characteristic of a parenchyma cell
The nucleotide sequence would have to have 900 nucleotides in order to code for a protein of 300 amino acids. When translating RNA into proteins, RNA is read 3 bases at a time. Each group of 3 bases is a codon, and each codon codes for an amino acid. When read, the proper amino acid is added to a growing chain of amino acids, which will be folded to become a protein.
Therefore, 300 amino acids * 3 nucleotides per amino acid = 900 nucleotides.
Many cells working together forms a tissue. Many tissues working together forms organs. Many organs working together forms organ systems. So it goes from general to most specific. Organ systems are needed in order for life. This proves that cells are the most basic units of life.
All the blood types are A+, A-, B+, B-, O+, O-, AB+, and AB-.