15. The main contributing factor to the release of CFC’s is
(A) decomposition in land fills.
(B) acid rain.
(C) emission from feedlots.
(D) leaking refrigerators and air conditioners.
(E) burning of tropical forests.

11. Most of the zygotic segmentation genes code for (A) special transfer RNA. (B) enzyme. (C) transcription factors. (D) histones. (E) transport proteins.

12. Most CO2 from catabolism is released during (A) glycolysis. (B) lactate fermentation. (C) the Krebs cycle. (D) electron transport. (E) oxidative phosphorylation.

13. The only taxon that actually exists as a natural unit is the (A) class. (B) family. (C) genus. (D) phylum. (E) species.

14. The organisms in your backyard include trees, shrubs, grass, ants, mushrooms, birds, spiders, beetles, flies, and bacteria. Together, all these organisms make up (A) an ecosystem. (B) a community. (C) a population. (D) an ecosociety. (E) an experimental group.

16. Lipids are absorbed by the ___ system. (A) urinary (B) blood vascular (C) reproductive (D) respiratory (E) lymphatic

17. The diploid sporophyte stage is dominant in the life cycles of all of the following except (A) a fern. (B) a moss. (C) a pine tree. (D) a dandelion. (E) a rose bush.

18. Which of the following is not a part of lichens? (A) fungi (B) green algae (C) brown algae (D) cyanobacteria (E) both C and D

19. Mark found an organism in a pond, and he thinks it’s a freshwater sponge. His friend Ralph thinks it looks more like an aquatic fungus. How can they decide whether it is an animal or a fungus? (A) See if it can swim. (B) See if it is a eukaryote or a prokaryote. (C) Look for cell walls under a microscope. (D) Determine whether it is unicellular or multicellular. (E) Figure out whether it is autotrophic or heterotrophic.

20. DNA replication occurs in (A) meiosis. (B) mitosis. (C) G1 phase. (D) G2 phase. (E) S phase.

21. A major difference in the mechanism of action between steroid and peptide hormones is that (A) steroid hormones mainly affect the synthesis of proteins, whereas peptide hormones mainly affect the activity of proteins already in the cell. (B) target cells react more rapidly to steroid hormones than they do to peptide hormones. (C) steroid hormones enter the nucleus, whereas peptide hormones stay in the cytoplasm. (D) steroid hormones bind to a receptor protein, whereas peptide hormones bind to G protein. (E) steroid hormones affect metabolism, whereas peptide hormones affect membrane permeability.