Sound is repeated near hills. why

Heat from the sun reaches earth to a. radiation b. convection c. conduction

Two thin 80.0- cm rods are oriented at right angles to each other. each rod has one end at the origin of the coordinates, and one of them extends along the x- axis while the other extends along the yaxis. the rod along the x- axis carries a charge of - 15.0 μ c distributed uniformly along its length, and the other rod carries 15.0 μ c uniformly over its length. find the magnitude and direction of the net electrical force that these two rods exert on an electron located at the point (40.0 cm, 40.0 cm). (e

The substances that are necessary for producing of certain hormones and that store and transport vitamins