PLEASE HELP ASAP WILL MARK BRAINLIEST Select ALL the correct answers.
Which of these factors make hydrogen fuel cells a better option than burning fossil fuels?
1.Hydrogen fuel cells have a higher energy efficiency.
2.Hydrogen fuel cells create less pollution.
3.Burning fossil fuels relies on outdated devices and technology.
4.Hydrogen is the most abundant element in the universe.
5.Hydrogen fuel cells are more expensive than fossil fuels.

If the demand function for a commodity is given by the equation p2 + 16q = 1200 and the supply function is given by the equation 300 − p2 + 2q = 0, find the equilibrium quantity and equilibrium price. (round your answers to two decimal places.)

The intensity, or loudness, of a sound can be measured in decibels (db), according to the equation , where i is the intensity of a given sound and is the threshold of hearing intensity. what is the intensity, in decibels, [i(db)], when ? use a calculator. round to the nearest whole number. 8 9 19 80

Follow these directions and answer the questions. 1. set up the ripple tank as in previous investigations. 2. bend the rubber tube to form a "concave mirror" and place in the ripple tank. the water level must be below the top of the hose. 3. generate a few straight pulses with the dowel and observe the reflected waves. do the waves focus (come together) upon reflection? can you locate the place where the waves meet? 4. touch the water surface where the waves converged. what happens to the reflected wave? 5. move your finger twice that distance from the hose (2f = c of c, center of the curvature) and touch the water again. does the image (the reflected wave) appear in the same location (c of c)? you may have to experiment before you find the exact location. sometimes it is hard to visualize with the ripple tank because the waves move so quickly. likewise, it is impossible to "see" light waves because they have such small wavelengths and move at the speed of light. however, both are examples of transverse waves and behave in the same way when a parallel wave fronts hit a curved surface.