With reference to different types of clouds, consider the following statements: I. High-altitude clouds composed mainly of ice crystals often appear thin and fibrous. II. Clouds that develop close to the Earth's surface are usually associated with vertical growth. III. Layered clouds that extend horizontally tend to cover large portions of the sky. IV. Dense, dark clouds are always responsible for prolonged rainfall only. Which of the statements given above is/are incorrect?

With reference to the Madden-Julian Oscillation (MJO), consider the following statements: I. It is an eastward-moving tropical disturbance rather than a stationary atmospheric trough. II. It is associated with alternating phases of enhanced and suppressed cloudiness, convection and rainfall. III. It generally operates within the tropical belt between 30°N and 30°S latitudes. IV. It can influence monsoon variability as well as tropical cyclone activity. Which of the statements given above are correct?

Which of the following correctly explains the formation of clouds in the atmosphere?