Nutrition labels tell you the nutrient content and calories per serving, which helps you plan meals by showing how a serving fits into your daily goals. With this information, you can compare products, adjust portion sizes, and manage overall intake of calories and nutrients to stay on target for your health plan. They aren’t about making meals tastier, locating stores, or automatically creating dietary restrictions; they’re a tool to understand what a serving contributes to your diet and to practice effective portion control.

When figuring energy needs for active adolescents, several factors drive how many calories the body uses each day. Growth requires extra energy to build new tissues. Puberty brings hormonal changes that can alter metabolism and energy needs. Activity level directly increases energy expenditure through movement and exercise. Body size influences metabolic rate—larger bodies typically burn more calories at rest and during activity. Climate affects energy needs because staying warm in cooler environments requires additional energy. Metabolic rate itself determines how efficiently the body uses fuel and can vary between individuals. Taken together, these factors provide a complete picture of what sets an adolescent’s energy needs. The other options miss multiple important pieces—for example, growth alone omits puberty, activity, size, climate, and metabolic rate; climate alone omits growth, puberty, activity, and size; sleep duration is not a primary driver of daily energy requirements for active teens.

Monitoring cardiovascular health centers on factors that raise the risk of heart disease and stroke. The three risk factors students should keep an eye on are high blood pressure, high cholesterol, and elevated blood glucose levels. High blood pressure means the heart must pump harder to move blood through the arteries, which over time can damage vessel walls and promote atherosclerosis. Because it often has no noticeable symptoms, regular blood pressure checks are essential, and management typically includes physical activity, weight control, a heart-healthy diet, and medications if prescribed. High cholesterol, especially elevated LDL cholesterol, contributes to the buildup of plaques inside arteries. This narrowing can restrict blood flow and increase the chances of a heart attack or stroke. A lipid panel helps track cholesterol and triglyceride levels, and improvements come from healthier eating, more activity, weight management, and, when needed, medication. Elevated blood glucose indicates impaired insulin action or diabetes, which accelerates damage to blood vessels and raises cardiovascular risk. Monitoring with fasting glucose or an A1C test shows whether glucose is in a safe range. Controlling glucose involves weight management, regular activity, balanced nutrition, and medications as advised. The other options describe conditions that aren’t risk factors—low values aren’t typically dangerous in this context—and protective practices like regular exercise and good sleep, which help reduce risk rather than indicate higher risk.

VO2 max is the maximum rate at which the body can take up, transport, and use oxygen during all-out, sustained exercise. This measure reflects the whole system’s aerobic capacity, integrating how well the lungs oxygenate blood, how effectively the heart and circulatory system deliver that oxygen, and how efficiently muscles utilize it at high intensity. It’s typically reported as milliliters of oxygen per kilogram of body weight per minute (mL/kg/min) and is determined during a graded exercise test with expired gas analysis. This isn’t the rate of energy production during digestion, which occurs after eating and isn’t tied to peak exercise performance. It isn’t resting metabolic rate, the energy used at rest, and it isn’t simply the oxygen-carrying capacity of the blood in the lungs. VO2 max specifically describes the body’s maximal ability to take in and use oxygen during peak effort, highlighting aerobic capacity.