Arabidopsis thaliana

1) The greatest proportion of water taken up by plants is:A Split during photosynthesisB Lost through stomata during transpirationC Absorbed by central vacuoles during cell elongationD Returned to the soil by rootsE Stored in the xylem

2) Plant hormones may be characterized by all of the following EXCEPT that they:A May act by altering gene expressionB Have a multiplicity of effectsC Function independently of other hormonesD Control plant growth and developmentE Affect division, elongation, and the differentiation of cells

3) Water flows into the source end of the sieve tube because:A Sucrose has diffused into the sieve tube from the companion cell making it hypertonicB Sucrose has been actively transported into the sieve tube, making it hypertonicC Water pressure outside the sieve tube forces in waterD The companion cell of a sieve tube actively pumps in waterE Sucrose has been dumped from the sieve tube by active transport

4) Plants can take up nitrogen from the soil in the form of:A Nitrate (NO3

-)B Ammonium ion (NH4

+)C N2D Only A and B are correctE A, B, and C are correct