Answer:
In our respiratory system, there is a pair of external nostril situated above the upper lip that receives atmospheric air and passed to the pharynx (a common passage for air and food). The pharynx passed this air to the trachea via larynx (known as the soundbox). The trachea is an extended part which is divided into left and right primary bronchi. Bronchi divide into secondary bronchi, tertiary bronchi, and bronchioles that ending up in thin terminal bronchioles. Each terminal bronchiole constitutes a number of irregular-walled, thin and vascularised bag-like structures called alveoli which are the primary sites of gases exchange.
C. living things respond to stimuli in the environment
Answer:
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Explanation:
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Answer:
4. cannot be made by the body and therefore must be consumed to maintain health.
Explanation:
Essential nutrients are nutrients that our body cannot synthesized and also those nutrients our body cannot produced in sufficient quantity, for the normal functioning of the body. These nutrients have to be obtained from the food we consume to support our life and health.
Essential nutrients obtained from food include carbohydrates, fats and oils, proteins, water, as well as certain vitamins and minerals. These essential nutrients that we get from our food are needed for good growth and development, prevention of diseases, as well as for maintaining good health.
<span>Controlled variable is a variable that was made constant in the research. That was because the controlled variables can influence the dependent or independent variable. If the variables is not made constant, it can alter the research result and made it invalid.
In this case, </span>the caffeine and alcohol intake might alter the physical activity or the blood glucose so it should be controlled.
