PLEASE HELPP 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 Burning fossil fuels relies on outdated devices and technology.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.

Animals respond in various ways to stimuli detected through their senses. some of these responses are stimulated by the presence of danger. which of these animal responses is the best example of a response to an immediate threat? a) a rooster crows every morning at the first sign of light. b) as something approaches an octopus, it shoots a cloud of ink. c) from late fall until spring, bears hibernate to preserve energy. reactivate d) a dog is getting hot in the sunlight, so he moves to a shaded area.

An ideal gas is held in a container at constant volume. initially, its temperature is 5 degrees c and its pressure is 1.2 atm. what is its pressure when its temperature is 43 degrees c? answer in units of atm

Light traveling in water, nwater = 1.33, strikes a plastic block at an angle of incidence of 51.4°; part of the beam is reflected and part is refracted. if the index of refraction of the plastic is 2.0, what is the angle made by the reflected and refracted beams?