Answer: billions of types of proteins
Receptors which provide animals with information from the external environment are located in ears, tongue, eyes, and the nose. These are all receptors that can be found in our sensory organs and provide us with feedback from our nearby environment and the stimuli on which we should be alerted towards.
Answer: Option b
Explanation:In chemistry,
before any reaction would occurs, reactat must be able to overcome some certain amount of energy which is called the activation. The activation energy is usually the heat that is suppled.it is also refered to as the minimum energy needed before any reaction can take place. For reaction to take place, there must be an equilibrium( at constant temperature and pressure.
