Sensing, secretion, protection, transcellular transport, and selective absorbtion
Answer:
Explanation:
The four elements been referred to here are hydrogen, oxygen, carbon and nitrogen.
These four elements constitute the majority of the human body because of a combination of factors. Although, some of these factors are the major reasons, for instance the human body is made up of cells which are the basic structures of life. The cell consists of over 70% of water (which is made of hydrogen and oxygen). Also, oxygen is inhaled through the process of respiration which combines with other molecules (such as haemoglobin to form oxyhaemoglobin) in the human body. These among others make oxygen the most abundant element in the human body.
Naturally occurring organisms usually have a high concentration of organic molecules (molecules made of majorly carbon and hydrogen). This makes the human body have a high percentage (after oxygen) of carbon and hydrogen. Also, carbohydrates (which are later converted to glucose) form a large part of our diet and are stored in the body as glycogen (causing the body to have a high amount of carbon and hydrogen atoms).
Nitrogen is an essential part/element found in amino acids which are building blocks of protein. Proteins are involved in several metabolic activities in the body; this makes the abundance of nitrogen the fourth (one of the four) most common element in the body. It should be noted that amino acids also have carbon and hydrogen elements also.
The combination of the factors above among some other factors make the human body comprise mainly of these four elements
Both it.) And I.) Can be answers. You could argue either one is right.
The reason animals need a continuous supply of oxygen is to<u> Obtain energy from their food.</u>
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The most fundamental reason why animals need a non-stop delivery of oxygen is without it animals can't achieve sufficient power from their meals.
Cells require a steady delivery of power to generate and preserve the biological order that keeps them alive. This electricity is derived from the chemical bond energy in food molecules, which thereby function as fuel for cells.
The animal's metabolism converts oxygen into strength. All through this system, a waste gas called carbon dioxide is produced. To remove it, the carbon dioxide is carried lower back to the lungs, where its miles are collected and exhaled.
Learn more about metabolism here: brainly.com/question/461228
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