Answer:
 An isotope is one of two or more forms of the same chemical element. Different isotopes of an element have the same number of protons in the nucleus, giving them the same atomic number, but a different number of neutrons giving each elemental isotope a different atomic weight.
Explanation:
pretty sure its D
 
        
             
        
        
        
Easy money because I’m just trying to get my brainly started
        
                    
             
        
        
        
They both act like filters. The coffee filter makes sure that coffee doesn't go in the drink and the kidney makes sure solids don't pass by.
 
        
                    
             
        
        
        
We can control it. It's just that our world "leaders" seem to use use money and drugs for other things. It cost money to even make money, yet, people don't want to spend it.
        
             
        
        
        
Answer:
The correct answer is d. Oxygen
Explanation:
Phytoplanktons are responsible for the fixation of approximately half of the global carbon therefore seawater has high CO2 concentration which is required by phytoplanktons to make their food.  
They are the primary producers of oceans and they are responsible to support the food chain of oceans. Factors that can limit their growth are mainly sunlight and nutrients like phosphorus, nitrogen, etc.
As phytoplanktons are photosynthetic they release oxygen itself as a byproduct therefore oxygen is not a limiting factor to phytoplanktons. So the right answer is d.