Unicellular protista with two flagellum that are photosynthetic and cause red tides are called a)amoebas b)ciliates c)dinoflagellates d)euglenoids

the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.

the law of original horizontality explains:   why rocks appear in layers. correct answer: b the law suggests that all rock layers are originally laid down (deposited) horizontally and can later be deformed.   the principle is used by geologists to make assumptions about the relative ages of sedimentary rocks.