During the Carboniferous Period,
A) the carbon dioxide cycle started to operate for the first time
B) carbon-rich meteorites impacted the Earth
C) the first carbon-based life appeared
D) land was covered with dense forests with the appearance of the first insects and amphibians
D
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A solid sphere, a solid cylinder, and a hoop each have the same mass and radius. If they are spinning at the same angular velocity, which one has the greatest rotational kinetic energy?
a. the sphere b. the cylinder c. the hoop d. They all have the same rotational kinetic energy.
The general theory of relativity depends on the fact that:
a. the mass m in Newton's law of gravitation always has the same value as the mass m in Newton's second law. b. inertial mass is measured by how objects respond to forces. c. gravitational mass is measured by comparing weights. d. gravitational mass is always greater than inertial mass. e. gravitational mass is always less than inertial mass.
Which of the following is true of Saturn's moon Titan?
A) It has extremely high temperature of about 290°F. B) It has oxygen in its atmosphere. C) It appears to have a liquid-water ocean below its icy crust. D) It is rich in organic molecules.
Both black and white road surfaces absorb sunlight. The warmer road surface at the end of a sunny day is the
A) black surface. B) white surface. C) neither of these