The oxygen molecules moves through the nostrils, pharynx, trachea, bronchus, smaller and smaller branches of the bronchial tree, and then into the alveolus.
Answer:
Viruses are not living things.
Answer: No.
Explanation:
Viruses are complicated assemblies of molecules, including proteins, nucleic acids, lipids, and carbohydrates, but on their own they can do nothing until they enter a living cell. Without cells, viruses would not be able to multiply.
A. is your correct answer.
Ïf is your answer your welcome
The answer is; A
When an impulse from the motor neuron reached the neuromuscular junction, the voltage-dependent calcium channels are activated and the neurotransmitter released from the presynaptic cleft. When the neurotransmitter binds to their receptors on the sarcolemma, the muscle fibers become depolarised; the calcium is released from their vesicles. The Ca2+ ions are important in the power stroke because they bind to troponin. Upon binding calcium, troponin moves tropomyosin away from the myosin-binding sites on actin. Powered by the energy from ATP molecule, the myosin is able to bind on the actin and slides over the actin filament.
