What evidence suggests that life was common on Earth within a billion years of its formation?
A) Life must have formed early in order to produce the variety of lifeforms seen today.
B) rocks older than 3.85 billion years with the carbon-12 to carbon-13 ratio typical of living organisms
C) 3.5 billion year old rock structures formed by microbes called stromatolites
D) A and C
E) B and C
E
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A metal rod of length 2.0 m is moved at 6.0 m/s in a direction perpendicular to its length. A 5.0 m T magnetic field is perpendicular to both the rod and its velocity. What is the potential difference between the ends of the rod?
A. 12 mV B. 60 mV C. 30 mV D. 15 mV E. 0
Graphical Analysis: An object is moving with constant non-zero velocity in the +x direction. The velocity versus time graph of this object is
A. a horizontal straight line. B. a vertical straight line. C. a straight line making an angle with the time axis. D. a parabolic curve.
A convex mirror with a focal length of -20 cm forms an image 12 cm behind the surface. If the object height is 1.2 cm what is the image height?
a. 0.30 cm c. 0.94 cm b. 0.48 cm d. 3.0 cm
Ceramics are often used in high ______________applications.
Fill in the blank(s) with the appropriate word(s).