When does a protostar become a true star?

Natural forces that can alter ecosystems include seasons and climate changes. t or f

Air enters a compressor operating at steady state at 1.05 bar, 300 k, with a volumetric flow rate of 93 m3/min and exits at 12 bar, 400 k. heat transfer occurs at a rate of 15.5 kw from the compressor to its surroundings. assuming the ideal gas model for air neglecting kinetic potential energy effects, determine the power in put in kw.

True or false: the revolution of the earth creates day and night as it rotates around the sun