The correct answer is (d.) proteins. Higher organisms use nitrogen to make their protein. Food that is containing protein also involves nitrogen in it. Protein also has amino acids that contain nitrogen in it which is a necessary essential nutrient for the body.
If DNA read A-T-T-A-C-G-G-C-C the RNA would be U-A-A-U-G-C-C-G-G
DNA replication is important because new cells require their own strand of the DNA. Without replication, there would be no new organisms because the DNA’s information would not be passed on.
Cardiac muscles as they have striations and are branching cells.