In the first question, coal and oil are produced when the remains of dead organisms are decayed in the presence heat and pressure but in the absence of oxygen therefore forming carbon-rich organic compounds and the absence of oxygen prevents the formation of carbon dioxide (which cannot be utilized as fuel). Therefore the correct answer is: Absence of oxygen, pressure and heat (semantically, it is supposed to be absence of oxygen, and the presence of pressure and heat).
In the second question, it is in the process of the water cycle. The water cycle starts when water is converted to water vapor in the presence of heat. Water vapor, being a light compound, rises up to the atmosphere and the cooler temperature of the higher levels of atmosphere condenses back the water vapor into water droplets hence the formation of clouds.Therefore, the correct answer is condensation.
