Answer: 2)
A mnemonic device
Explanation: A mnemonic is a tool or memory aid that helps people to remember or memorize things easily. It helps you to remember an idea or phrase with a pattern of letters, numbers, or relatable associations. Mnemonic devices may include special rhymes and poems, acronyms, images, songs, outlines, and other tools. In the question Luke makes up a sentence using the first letter from each base as the first letters for his words, repeating to himself to help him remember more easily the bases of DNA. In other words Luke formed mnemonics using the first letters of the DNA bases to remember them easily.
Nitrogen-containing biological compounds found in DNA/RNA/nucleotides/and nucleosides
Gut bacteria include Lactobacillus, the bacteria commonly used in probiotic foods such as yogurt, and E. coli bacteria. About a third of all bacteria in the gut are members of the Bacteroides species. Bacteroides are key in helping us digest plant food.