Answer:Spectroscopy helps astronomers to determine the composition, temperature, density, and motion of an object.
Infrared spectroscopy helps to identify the atoms and molecules in the object.
The red shift or blue shift (Doppler Effect) in a spectral line tells how fast the object is receding from Earth or coming toward it.
The Doppler shift enables astronomers to discover extrasolar planets.
As a planet orbits its star, the star is alternately moving away from or toward us.
Astronomers can use the Doppler shifts to calculate the speed of the star and the mass of the planet that is tugging on it.
Explanation:
 
        
                    
             
        
        
        
The right choice would be A
        
             
        
        
        
Answer:
Resident microflora b. may be responsible for opportunistic infections in immunocompromised
Explanation:
It is almost impossible to found these microorganisms in the stomach because of the acidic conditions, most of them are not adapted to this type of environment. Resident microflora is not transient, is actually permanent. However, resident microflora may be responsible for ooportunistic infections in immunocompromised and they can also increase the intensity of the disease produced by that pathogen.
 
        
             
        
        
        
True, Methane is a greenhouse gas