A typical stellar spectrum (a plot of intensity versus wavelength) includes a number of deep indentations in which the intensity abruptly falls and then rises. These deep indentations are called lines.

They are called absorption lines

Explanation:

Absorption lines are defined as dark lines or lines having reduced intensity, on an ongoing spectrum. A typical example is noticed in the spectra of stars, where gas existing in the outer layers of the star absorbs some of the light from the underlying thermal blackbody spectrum.

which piece of furniture will have the most inertia and give the furniture movers the most difficulty in moving?  

answer

a 75kg dining table

talk back to him about the sport and show him your expertise or leave the room