d. scientific theory
Explanation:
The statement that all living things like planktons are made up of cells is a true scientific theory. 
All living organisms are made up of cells and all cells are derived from pre-existing cells is the first and most fundamental postulate of the cell theory. 
- the concept that living things are made up of cell is from the cell theory. 
- the cell is the fundamental unit of life. 
- the cell theory provides an explanation into cells as the unit of life
learn more: 
Cell theory brainly.com/question/3256177
#learnwithBrainly
 
        
             
        
        
        
The correct answer is: 4) Standing defenses are always present; induced defenses develop in response to a threat
Induced defense is defense that can be changed or invoked when needed. Induced defenses are slow to happen. When invoked, induced defense requires energy but otherwise doesn’t.
Standing defense is always there. It is use, for example when predation is a constant threat.
 
        
             
        
        
        
A I believe should be correct
        
                    
             
        
        
        
 
The ER functions as a manufacturing and packaging system. #markasbrainliest