What is an educated guess posed as a tentative explanation called ?

Common symptoms of an iron-defiency anemia include muscle weakness shortness of breath and lightheadedness why does iron deficiency causes these symptoms

Aragonite shells of clams, snails, or scleractinian corals may be preserved unaltered in cenozoic deposits, but they are generally dissolved or recrystallized in older deposits. true or false

In what locations does this text suggest you might find zooflagellates living? fresh water lakes on the surface of leaves inside other organisms on damp forest floors