Five observational evidences are: 1. the expansion of the universe. 2. the abundances of the light elements: H, D, He, and Li. 3. the existence of the cosmic microwave background (CMB). 4. that the fluctuations in the CMB are accounted for by primordial density fluctuations that account adequately so far for the initial conditions for the large- scale structure of the universe. 5. that the oldest stars ( > 13.6 Gyr) are not older than the observable universe. These evidences strongly support: a) Big Bang cosmology. b) the steady-state universe. c) little bang cosmology. d) the hierarchical universe. e) Democritean cosmology. 52. "Let's play Jeopardy! For $100, the answer is: This concept offers possible solutions to three problems of cosmology: the magnetic monopole, horizon, and flatness problems." What is , Alex? a) the cosmological constant b) the Einstein universe c) Big Bang cosmology d) inflation e) perdition 53. The heat energy of a fluid in heat engine (e.g., steam engines and internal combustion engines) is usually transformed into macroscopic energy (e.g., macroscopic kinetic, potential, and electrical energies) by means of the in a piston. a) Force b) elastic force c) pressure force d) given force e) relief force