Answer:
Rotation of Earth while orbiting the sun.
The right answer is It connects amino acids.
• Amino acids are the building blocks of proteins.
• There are 21 amino acids, but only one type of binding used to connect them: it is the peptide bond.
The peptide bond is formed during the translation step by a covalent bond between an α-amino group of an amino acid and the carboxylic group of another amino acid. A molecule of water is eliminated.
Answer: we can make observations directly by seeing, feeling, hearing, and smelling, but we can also extend and refine our basic senses with tools: thermometers, microscopes, telescopes, radar, radiation sensors, X-ray crystallography, mass spectroscopy, etc. And these tools do a better job of observing than we can!