You are building a shelf at home. as you sand the wood dust floats into the air. the air and dust from sanding create which of the following.
a. a solution
b. a pure substance
c. a colloid
d. a suspension

A colloid and a suspension are the same thing so it rules out c and d because the dust is heavier than air causing it to float down but not float constantly. a pure substance is one solid substance. so its be A. a solution. a solution is a homogenous mixture of 2 or more substances because it wouldn't only compose of wood dust because of the air oxygen and carbon dioxide keeping it from falling faster.

The predicted location of Neptune was made possible because of the radio telescope. The main part of the radio telescope was detecting the radio emissions made by natural celestial objects or by artificial satellites. It is a kind of radio antenna that absorbs the radio signals. An engineer of Bell Telescope laboratories was the first to create a type of radio telescope.