<span>b. It ensures that measurements are taken from two points
that are very far apart.
Measurements taken six months apart are the farthest apart
that an astronomer can ever get ... they're on opposite sides
of the Earth's orbit !</span>
Violet. Red is longest wavelength and lowest frequencyViolet is shortest wavelength and highest frequencyThe visible part of the whole electromagnetic spectrum.Sort of thing you see if you look through a prism in an laboratory optical spectrometer.
Answer:
Option A
Explanation:
The Equation represents the displacement of the object which is represented by x

so,
means when time is zero so we replace t with zero in the equation,

now for v which is velocity we need to differentiate the function as the formula for velocity is rate of change of displacement over time so we derivate the equation once and get,

now for
we insert t = 0 and get

now for a which is acceleration the formula of acceleration is rate of change of velocity over time, so we differentiate the the equation of v(velocity) once or the equation of x(displacement) twice so now we get,

so Option A is your answer.
Remember derivative of a constant is always zero because a constant value has no rate of change has its a constant hence the derivative is 0