If enough evidence accumulates to support a hypothesis, it moves to the next step — known as a theory — in the scientific method and becomes accepted as a valid explanation of a phenomenon. Tanner further explained that a scientific theory is the framework for observations and facts.
 
        
             
        
        
        
The correct answer is a. Complex
A complex or undefined medium is rich in nutrients, which contain water-soluble extracts of plant or animal tissue, a sugar, (often glucose is added to serve as the main carbon and energy source). The combination of extracts and sugar creates a medium which is rich in minerals and organic nutrients, but the exact composition is unknown.
 
        
             
        
        
        
I know this is a little late but i thought i should still tell you that its the endocrine organ
        
             
        
        
        
True - An extensive chain of mountains or mountain ranges, especially the principal mountain system of a continent.
        
             
        
        
        
Answer:
The Oxygen liberated in photosynthesis comes from photolysis of water.
The CHO formed from Calvin Cycle during photosynthesis comes from reduction of CO2 with H+ of photolysis of water.
Therefore,since Plant 1 contains labeled Oxygen(from water) it will give radioactive Oxygen as the byproduct of its photosynthesis. It CHO is normal.
However,Plant 2, will contain radioactive CHO,because its radioactive CO2 will be reduced by H+  from photolysis of water to form radioactive labeled  carbohydrate(CHO)
Explanation: