Answer:
In everyday language a theory means a hunch or speculation. Not so in science. In science, the word theory refers to a comprehensive explanation of an important feature of nature supported by facts gathered over time. Theories also allow scientists to make predictions about as yet unobserved phenomena".
Explanation:
 
        
             
        
        
        
The answer is true. They cannot only replicate themselves within cells, but they cannot outside of a cell.
        
                    
             
        
        
        
C. The digestive system breaks down food and the circulatory system transports the nutrients throughout the body.
The Digestive system is the system that helps the body digest food. It consists of the following organs: liver, stomach, gallbladder, large and small intestines, pancreas, rectum, and esophagus.
The Circulary system is the system that pumps blood through body. The blood contains all the nutrients and minerals the body needs. The system consists of the following organs: heart, blood vessels, blood, lymph, lymphatic vessels, and glands.
        
                    
             
        
        
        
Heat, light, sound and fire may have been involved when the Bunsen burner was lit with the spark from the Van de Graaff generator. Bunsen burner is a common device in the lab.
<h3>What is a Bunsen burner?</h3>
Bunsen burner is a laboratory device (gas burner) that generates a single open gas flame.
The gas most commonly used in Bunsen burner is generally natural gas, i.e., methane gas.
This device (Bunsen burner) can be used to generate a heat source during a lab experiment. 
Learn more about the Bunsen burner here:
brainly.com/question/10281181
 
        
             
        
        
        
The right option is c. consumed
in place of; consumed together with
A substitute is a good that is consumed
in place of another good, and a complement is a good that is consumed together
with another good. Substitutes serve in place of another and complements make
something seem better.