What radionuclide has a well-known percentage
content in all living organisms until the time that
they die, and so can be used to determine how
long fossil samples have been dead?
a) carbon-14
b) carbon-12
c) uranium-238
d) uranium-235
a
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Suppose you live at latitude 20°N. Based on the given right ascensions and declinations, which of the following stars passes closest to your zenith on its daily path through your sky?
A) Sirius: RA = 6hr 45m, dec = -16°42' B) Canopus: RA = 6hr 24m, dec = -52°41' C) Alpha Centauri: RA = 14hr 40m, dec = -60°50' D) Arcturus: RA = 14hr 16m, dec = +19°11' E) Vega: RA = 18hr 37m, dec = +38°47'
Which of the following has virtually no effect on the internal structure of a planet?
A) its size B) its composition C) its magnetic field D) its mass
What factors are important when trying to classify a spiral galaxy?
a. Amount of dust and gas in the galaxy b. Structure of the spiral arms c. Size of the central region d. All of the above
Type Sc are the dustiest and flattest of the galaxies
Indicate whether the statement is true or false