The oceans are primarily composed of which two elements? Carbon and hydrogen
Calcium and silicon
Hydrogen and oxygen
Nitrogen and phosphorus

Which group of algae is characterized by unicellular organisms and includes some members that would be better classified as zooflagellates? euglenophytes red algae sporozoans green algae

Which is not a type of symmetry? a. asymmetryb. radial symmetryc. bilateral symmetryd. lateral symmetry

Which is an example of a vestigial structure? a. tail of a monkey b. fin of a fish c. flower of a plant d. tailbone of a human