Oxygen and glucose are need for cellular respiration
Answer: Covalent bonds form when atoms share their valence electrons with other atoms to become a more stable molecule.
Explanation: Atoms form covalent bonds as a result of the Octet Rule. The Octet Rule states that all atoms in a molecule need to have eight electrons in their valence shell. This rule can be satisfied by sharing, losing or gaining electrons. A covalent bond allows atoms to satisfy the Octet Rule via sharing.
Answer:
Endocrine glands make chemicals called hormones and pass them straight into the bloodstream. Hormones can be thought of as chemical messages. From the blood stream, the hormones communicate with the body by heading towards their target cell to bring about a particular change or effect to that cell