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371 . Usually when tomatoes are plucked they are green. They become red later because the
A. Chromoplast gets converted into chloroplast
B. Chloroplast gets converted into chromoplast
C. Chloroplast disappears and new chromoplasr arises
D. None of the above

372 . Which of the following is used by green plants for the manufacture of sugar?
A. Water B. Sunlight 
C. Carbon dioxide D. All of the above

373 . A radar that detects the presence of an enemy aircraft uses -
A. Sound waves B. Radio waves
C. Electric waves D. Ultrasonic waves

374 . Which one of the following elements is present in green pigment of leaf?
A. Iron B. Calcium
C. Phosphorus D. Magnesium

375 . Iron sheet kept in moist air gets covered with rust. Rust is -
A. an element
B. a compound
C. a mixture of iron and dust
D. a mixture of iron, oxygen and water