ecology

3. smaller spore that produces a male gametophyte in a heterosporous plant
4. arrangement of leaves on a stem
6. xylem cell with thick secondary walls that helps transport water
7. study of the geographic distribution of living things and the abiotic factors that affect their distribution
10. consumption of plants by insects and other animals
13. sac-like structure at the tip of the stamen in which pollen grains are produced
14. related group of angiosperms that produce embryos with one cotyledon and pollen with a single ridge
17. leaf without a petiole that is attached directly to the plant stem
18. invertebrates found within the calcium carbonate substrate of coral reefs
19. ground tissue found between the vascular tissue and the epidermis in a stem or root
20. dominant phylum of gymnosperms with the greatest variety of trees
21. modified underground stem adapted for starch storage; has many adventitious buds

1. growth and development of plants in response to light
2. ground tissue found towards the interior of the vascular tissue in a stem or root
5. eudicot) related group of angiosperms whose embryos possess two cotyledons
8. plant structure with a tight arrangement of sporophylls around a central stalk, as seen in cones or flowers; the male strobilus produces pollen, and the female strobilus produces eggs
9. gymnosperm with one extant species, the Ginkgo biloba: a tree with fan-shaped leaves
11. pattern of leaf arrangement in which three or more leaves are connected at a node
12. region between nodes on the stem
15. chamber that contains and protects the ovule or female megasporangium
16. grass-like plant noticeable by the absence of woody tissue