During the Precambrian, the development of the ozone layer helped
A) primitive organisms on Earth's surface to nucleate.
B) shield Earth's surface from harmful ultraviolet radiation.
C) promote the emergence of stromatolites.
D) promote the development of anaerobic organisms.
Answer: B
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Acceleration: Suppose that a car traveling to the west (-x direction) begins to slow down as it approaches a traffic light. Which statement concerning its acceleration must be correct?
A. Its acceleration is positive. B. Its acceleration is negative. C. Its acceleration is zero. D. Its acceleration is decreasing in magnitude as the car slows down.
A 400-g piece of metal at 100°C is dropped into a cup containing 450 g of water at 15.0°C. The final temperature of the system is 40.0°C
What is the specific heat of the metal, assuming no heat is exchanged with the surroundings or the cup? A) 1960 J/(kg?K) B) 2830 J/(kg?K) C) 3420 J/(kg?K) D) 3780 J/(kg?K) E) 4280 J/(kg?K)
The maximum permissible workday dose for occupational exposure to radiation is 11 mrem. A 77-kg laboratory technician absorbs 2.3 mJ of 0.5-MeV gamma rays in a work day
The relative biological effectiveness (RBE) for gamma rays is 1.00. What is the number of gamma-ray photons absorbed by the technician in a workday? A) 3 × 1010 B) 3 × 109 C) 3 × 108 D) 1 × 109 E) 1 × 108
Origin of Fossil Fuels
What will be an ideal response?