A hot‐air balloon stays aloft because hot air at atmospheric pressure is less dense than cooler air at the same pressure. If the volume of the balloon is 500. 0 m3 and the surrounding air is at 15. 0°c, what must the temperature of the air in the balloon be for it to lift a total load of 290 kg (in addition to the mass of the hot air)? the density of air at 15. 0°c and atmospheric pressure is 1. 23 kg/m3.

Spider crabs live in the shallow regions of the ocean floor. algae tend to grow on the surface of spider crabs. the algae provide the crabs protection from predators by camouflaging them. the spider crabs give the algae shelter. what does this description suggest? 1. the algae are parasites of the spider crabs. 2. the algae and the spider crabs have a mutualistic relationship. 3. the spider crabs are commensals, and the algae are parasites. 4. the spider crabs benefit from the algae living on them. 5. the spider crabs are parasites of the algae.