C:Primary cause i was asked this question and that is what the answer was
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
Answer:This is an example of a theory changing because a new scientific method was developed.
Explanation:
They are colorless plastics
This would be A, herbicides is a chemical used by humans not plants!
