<em>A megaphone used by a cheerleader can allow people on the opposite side of a field to hear her better because;</em>
D. Solid objects can change the direction of sound waves; megaphones allow users to determine the general direction of the sound.
<u>Determination of the general direction of the sound lessens its dispersion and thus, it reaches the observers at a higher intensity, hence it being louder.</u>
Answer:
All chemical reactions involve energy.Energy is used to break bonds inreactants, and energy is released when new bonds form in products. Endothermic reactions absorb energy, and exothermic reactions releaseenergy. The law of conservation ofenergy states that matter cannot be created or destroyed.
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.
