In a cactus, carbon is fixed only during the day. this is because cacti need sunlight to perform photosynthesis. Have a great day :)
        
             
        
        
        
Answer:
Neuroimaging, or brain scanning, includes the use of various techniques ( Four of the most common types of brain scans are EEG, PET, MRI, and fMRI )to directly or indirectly image the structure, function, or pharmacology of the brain
Explanation:
Electroencephalography (EEG) is used to show brain activity under certain psychological states, such as alertness or drowsiness.
Positron emission tomography (PET) scans show brain processes by using the sugar glucose in the brain to illustrate where neurons are firing.
Magnetic resonance imaging (MRI) scans use echo waves to discriminate among grey matter, white matter, and cerebrospinal fluid.
Functional magnetic resonance imaging (fMRI) scans are a series of MRIs measuring brain function via a computer’s combination of multiple images taken less than a second apart. With this different scan it is possible for the function and structure of the brain to be determined. 
 
        
                    
             
        
        
        
Answer:
Mississippian fossils are abundant in portions of the Midwest and South and include vast beds of limestone and marble. 
Explanation:
For example, the domed ceiling of the Jefferson Memorial in Washington, D.C., is made of Indiana limestone that was deposited during the Mississippian Period.By the end of the Carboniferous, reptiles had migrated well toward the interior of Pangea. These early pioneers went on to spawn the archosaurs, pelycosaurs, and therapsids of the ensuing Permian period. (It was the archosaurs that went on to spawn the first dinosaurs nearly a hundred million years later.)
 
        
             
        
        
        
Is spread from one person to another through a variety of ways that include: contact with blood and bodily fluids; breathing in an airborne virus; or by being bitten by an insect.