Answer:
D. Alveoli
Explanation:
Functionally, the respiratory system is separated into a conducting zone and respiratory zone:
Conducting zone consists of the nose, pharynx, larynx, trachea, bronchi, and bronchioles. These structures form a continuous passageway for air to move in and out of the lungs.
Respiratory zone is found deep inside the lungs and is made up of the respiratory bronchioles, alveolar ducts, and alveoli. These thin-walled structures allow inhaled oxygen (O2) to diffuse into the lung capillaries in exchange for carbon dioxide (CO2).
The respiratory zone begins where the terminal bronchioles join a respiratory bronchiole, the smallest type of bronchiole, which then leads to an alveolar duct, opening into a cluster of alveoli.
First comes fertilization, when two gametes combine to form a zygote.
The answer is C - an explanation based on observation, experimentation, and reasoning.
The reason why the correct answer is C and not D is because D would most likely be a hypothesis. Each hypothesis corresponds to an idea that needs empirical testing and we want to see if it's true or not.
A theory on the other hand is a general collection of possibly multiple hypothesis that have been tested and confirmed. A theory incorporates a more conclusive framework under which scientists can test their hypothesis.
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Mutations can happen in every stage of a cell cycle. Also most DNAs code for functional RNA not proteins. And only some mutations are beneficial not Mostly. Pay attention on the fact that in one cell we have complete set of genes but only a few of them express ( activated)
