The distribution of galaxies in the universe is not regular, but clumpy. galaxies, some of them one billion light years from the sun, tend to clump together into huge supercluster formations. this is an image of the perseus-pisces supercluster. some galaxies are visible with the naked eye, but astronomers discovered these distant galaxies with the of a) space probes. b) satellite imaging. c) manned space craft. d) x-ray and infrared telescopes.

Which missing item would complete this alpha decay reaction ? > 228/88ra + 4/2he a.224/96 rn b. 232/90 th c. 230/92 u d. 235/92 u

1. what is the relationship between wavelength and the penetrating power of an electromagnetic wave? a) the penetrating power has no relationship to the wavelength. b) the penetrating power increases as the wavelength increases. c) the penetrating power decreases as the wavelength increases. d) the penetrating power decreases as the wavelength decreases. 2. as ice melts and turns into water, the speed of sound through the material would most likely do what? justify your answer. a) the speed would not change because the material is always water. b) the speed of sound would increase because the density of water is less than that of ice. c) the speed of sound would increase because energy is added to ice in order to make it melt. d) the speed of sound would decrease because sound travels faster through solids than liquids. 3.which of these waves need a medium to travel through? a) sound b) x-rays c) infrared rays d) visible light

Which of the following statements are true for an isothermal process? check all that apply. - during an isothermal process, the work done by the gas equals the heat added to the gas. - during an isothermal process, the internal energy of the system changes. - an isothermal process is carried out at constant temperature. - an isothermal process is carried out at constant pressure. - an isothermal process is carried out at constant volume.