Which of the following is an extinct group of mollusks related to today's chambered nautilus?
a. trilobites
b. ammonites
c. foraminifera
d. stromatolites

Cells tend to have a relatively small and uniform size. why aren’t cells larger?

What have we learned from fossil evidence about evolution? a) it is an abrupt change. b)the process is observable. c) it takes place during one lifetime only. d)the most complex traits are always selected.

Which best describes how the common cold spreads in the human body? a bacteria burst out of normal cells killing them b viruses replicate inside respiratory cells c bacteria inject dna into normal cells d viruses insert dna into bacteria