the awnser to ur question is D
(a) The gas of interstellar medium can be detected from the radiations of photons of wavelength 21 cm.
(b) The gas of interstellar medium can be detected from the absorption lines present in the light from distant stars, which must be caused by a medium of density and temperature other than that of the stars emitting the lights.
<h3>
What is interstellar medium?</h3>
Interstellar medium is the matter and radiation that exist in the space between the star systems in a galaxy.
<h3>Evidence that interstellar medium contains both gas and dust</h3>
- The gas of interstellar medium can be detected from the radiations of photons of wavelength 21 cm.
- The gas of interstellar medium can be detected from the absorption lines present in the light from distant stars, which must be caused by a medium of density and temperature other than that of the stars emitting the lights.
Learn more about interstellar medium here: brainly.com/question/4173326
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The object will move if the forces are unbalanced.
Newtons second tells you that when a net force (the unbalanced force) is applied to and object it will produce an acceleration (movement) in direct proportion to the force and in inverse proportion to the mass of the object.
Answer:

Explanation:
As we know,
=》Force = Mass × Acceleration
=》45 N = 0.75 × Acceleration
=》Acceleration = 45 ÷ 0.75
=》Acceleration = 60
hence, the Acceleration of the ball would be. 60 meters per second square
