Answer:
Their speed in a vacuum is a constant value.
Explanation:
Electromagnetic waves consits of oscillations of electric field and magnetic field. The oscillations of these fields occur in a direction perpendicular to the direction of propagation of the waves, so they are transverse wave. Electromagnetic waves, contrary to mechanical waves, do not need a medium to propagate, so they can also travel through a vacuum. In a vacuum, their speed is constant and has always the same value, the speed of light:

Compared with an Earth year, a galactic year represents time on a grand scale but its not a consistent measurement across the galaxy
Answer:
a)
, b)
, c) 
Explanation:
a) The initial potential energy is:


b) The efficiency of the bounce is:


c) The final speed of Danielle right before reaching the bottom of the hill is determined from the Principle of Energy Conservation:





Answer:
A) Magma emplacement
Explanation:
Sedimentary structures forms during deposition of sediments. It can also form after sediments have been deposited. Sedimentary structures can only be found in sedimentary rocks. Some examples include mud cracks, ripple marks, cross stratification, potholes, etc
Magma emplacement is an igneous process which describes the different mechanisms by which magma can be emplaced. It is only typical of igneous rocks.