During the period of one day, the number of high tides at a given location is about __________.
Fill in the blank(s) with correct word
Question 2
What is a gluon?
a. A flavor of quark.
b. The most newly discovered lepton.
c. A combination of three complementary quarks.
d. A particle exchanged by quarks.
e. A particle exchanged by electrons to give electrical repulsion.