Answer:
an opening into a vessel or cavity of the body.
Answer:
Respiration begins at the nose or mouth, where oxygenated air is brought in before moving down the pharynx, larynx, and the trachea. The trachea branches into two bronchi, each leading into a lung. Each bronchus divides into smaller bronchi, and again into even smaller tubes called bronchioles.
Answer: Gemstones of various minerals are highly prized for beauty, durability, and rarity. Some noncrystalline materials of organic origin. Examples are pearl, red coral, and amber also are classified as gemstones. Gemstones have attracted people since the ancient times, and have been used for jewelry.
Explanation: