Ray is studying the Texas prairie ecosystem and is starting off by identifying all the abiotic and biotic factors in that ecosystem. Which of the following lists contains only biotic factors? A water, temperature, amount of daylight, soil
B grasses, bacteria, flowers, insects, birds
C deciduous trees, woody plants, water
D bacteria, protists, fire, plants, animals

Air initially at 0.75 bar, 1000 k, and occupying a volume of 0.12 m^3 undergoes two processes. process 1-2: the air is compressed isothermally until the volume is halved. process 2-3: the air undergoes a constant pressure process until the volume is halved again. assume ideal gas behavior. a) determine the mass of the air, in kg. b) the work and the heat transfer for each of the two processes, in kj. (100 kj = 1 bar . m^3)

Work = force × a. work b. energy c. distance d. momentum

How is sound energy produced a. vibrating objects b. objects being heated c. temperature differences d. stationary objects