Sarah performs an experiment to determine the effect of nitrogen on plants. She studies the effect of nitrogen on the growth of the root hair, height of the plants, and nodule formation. Which factor is an independent variable?

Arrange the following in the correct sequence, from earliest to most recent, in which these plant traits originated. 1. sporophyte dominance, gametophyte independence 2. sporophyte dominance, gametophyte dependence 3. gametophyte dominance, sporophyte dependence a) 1 → 2 → 3 b) 2 → 3 → 1 c) 2 → 1 → 3 d) 3 → 2 → 1 e) 3 → 1 → 2

All ova contain sex chromosomes corresponding to: x y xx xy

The ultimate purpose of respiration: a. inhale 02 and exhale co2 b. place oxygen in the lungs c. place oxygen in the blood d. deliver oxygen to every blood cell