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:
 
        
                    
             
        
        
        
Answer:
This question is incomplete but the completed question is below
eeds that are planted upside down are still able to grow into mature plants. Which explanation best explains this phenomenon?
(a)The roots change into branches, and the branches turn into roots.
(b)The roots grow toward the force of gravity, and the shoots grow away.
(c)The plant will become a smaller version of a mature plant.
(d)Roots always grow toward the dark, and shoots grow toward the light.
Two options appear to be correct here: options B and D
Explanation:
Regardless of the direction the seed is planted, the seed has the ability to re-position itself via the help of growth hormones that respond to gravity and redirect the seed into the proper orientation. However, after re-orientation of the seed, the root grows toward the direction of gravity (a process known as gravitropism) while the shoot grows toward the direction of sunlight (a process known as phototropism). Even though two options appear to be correct here, the most correct option based on he question is b