Answer:
The correct answer is option c) "organs".
Explanation:
One of the characteristics that define an organ is to have different layers of tissue, which fits the description that an organ must be comprised of at least two different kinds of tissue. The fact that a serous membrane contains superficial and deeper layers of epithelial and connective tissues, grants it the category of being an organ.
 
        
             
        
        
        
Answer:
B. a nonspecific defense against infection
Explanation:
 
        
                    
             
        
        
        
Light excites the electrons in chlorophyll a molecules of photosystem 1. As these electrons move to another primary electron receptor, electrons from photosystem 2 replace them.
Therefore the answer is FROM PHOTOSYSTEM 2.
        
             
        
        
        
Answer:all the things that you keep the same in the experiment 
Explanation:
 
        
                    
             
        
        
        
The eons that make up 90% of Earth's history are the Precambrian eons, which consists of Hadean, Archean, and Proterozoic eons.