551. The size of Covid-19 virus is______?
A. 25-30KB
B. 28-30KB
C. 29-30KB
D. None of these

552. Which component of diet helps in preventing constipation ?
A. Proteins
B. Fats
C. Fiber
D. Carbohydrates

553. The over-cooking of food should be avoided because____________?
A. Make the food difficult to digest
B. Reduce the nutrition value of food
C. Make food Poison
D. None

554. The Planet which revolves slowly around the Sun is__________?
A. Mercury
B. Mars
C. Earth
D. Neptune

555. The Saturn rings discovered by___________?
A. Newton
B. Robert Brown
C. Galileo
D. None of these

556. Water has been discovered on which potentially habitable super-Earth ?
A. K2-14d
B. K2-15c
C. K2-13a
D. K2-18b

557. The lenses are used for the correction of:____________?
A. Long-sightedness
B. short sightedness
C. Both A & B
D. None of those

558. Nervous system includes which of these major components?
A. Brain
B. Brain & Back Bone
C. brain, spinal cord and neurons
D. None

559. Sound travels about ___________times faster in water than in air.
A. 2
B. 3
C. 4
D. 5

560. speed of sound in dry air at 20 °C is___________?
A. 353 m/s
B. 345 m/s
C. 343 m/s
D. none of them