Plants use what from air to make nitrogen

Carbon         

A student believes that a beverage improves memory. Two groups of students will be given a beverage before they take a test in class.  
Which of these is the best way for the student to design the experiment?
A.One group should be given the beverage, the other group should be given water.
B.One group should be given beverage, the other group should be given diet version of the beverage.
C.One group should be given a math test, the other group should be given a science test.
D.One group should be given the beverage, the other group should be given beverage diluted in water.

Carbon         

A student believes that a beverage improves memory. Two groups of students will be given a beverage before they take a test in class.  
Which of these is the best way for the student to design the experiment?
A.One group should be given the beverage, the other group should be given water.
B.One group should be given beverage, the other group should be given diet version of the beverage.
C.One group should be given a math test, the other group should be given a science test.
D.One group should be given the beverage, the other group should be given beverage diluted in water.

The answer is carbon

The answer is carbon

Long term continuous groundwater monitoring, especially with warning systems and anthropic activity monitors