Answer: leftover radiation from the big bang
Microwave background radiation is a form of electromagnetic radiation that is present in the whole universe and completely fills it.
Its frequency belongs to the microwaves range and is one of the main demonstrations of the of the Big Bang theory model.
It is important to note the Big Bang occurred 400,000 years before the events related to the microwave cosmic radiation, this means the Big Bang occurred first.
Answer: spectroscopy
Spectroscopy is the separation of the light in the different wavelengths and spectrophotometry measures the intensities of the different components of the light to get the composition of substances.
I don’t see a picture but unbalanced forces could be two boys pushing with a combined force of 400 Newton’s but the surface of what the box is laying on being 600 meaning since the ground is creating a higher force in the form of friction it will slow the boys down. When forces are unbalanced it means that the object can not be still or moving at a constant speed when one force is greater by a significant amount the object either slows quickly or accelerates fast depending on which factor is greater.