Elastic cartilage and most hyaline cartilages are surrounded by a protective sheath called a:.

Perichondrium

Explanation:

Elastic cartilage (like hyaline cartilage) has chondrocytes located in lacunae and the tissue is surrounded by a perichondrium. The perichondrium (Figure 7–2) is a sheath of dense connective tissue that surrounds cartilage in most places, forming an interface between the cartilage and the tissues supported by the cartilage. The perichondrium harbors the blood supply serving the cartilage and a small neural component. Articular cartilage, which covers the ends of bones in movable joints and which erodes in the course of arthritic degeneration, lacks perichondrium.

i think it's they require warm air

explanation:

tornados usually happen when it's raining right so when it's raining it cools down so if the temperature keeps changing then i think a tornado occurs sorry if it's wrong

both anaerobic and aerobic respiration use glucose (or other carbohydrates), proteins and lipids to produce atp and nadh. cell uses those energy molecules, obtained from food and   breaks them down during the chemical reactions of respiration. in anaerobic respiration, nadh is regenerated to nad+ by enzymes lactate dehydrogenase (lactate is produced, e.g. in muscle cells) or by alcohol dehydrogenase where ethanol is produced (alcohol fermentation), while in aerobic respiration, electrons from nadh are deposited in the mitochondria to regenerate nad+ (electron transport chain. anaerobic respiration produces 2 atp per molecule of glucose compared to aerobic respiration where about 38 atp molecules are produced.