abdomen posterior part of an arthropod's body (p. 721)
abiotic factor - physical, or nonliving, factor that shapes an ecosystem (p.90)
abscission layer - layer of cells at the petiole that seals off a leaf from the vascular system (p. 642)
accessory pigment - compound other than chlorophyll that absorbs light at different wavelengths than chlorophyll (p. 506)
acellular slime mold - slime mold that passes through a stage in which its cells fuse to form large cells with many nuclei (p.516)
acetylcholine - neurotransmitter that diffuses across a synapse and produces an impulse in the cell membrane of a muscle cell (p. 929)
acid - compound that forms hydrogen ions (H+) in solution (p.43)
abiotic factor - physical, or nonliving, factor that shapes an ecosystem (p.90)
abscission layer - layer of cells at the petiole that seals off a leaf from the vascular system (p. 642)
accessory pigment - compound other than chlorophyll that absorbs light at different wavelengths than chlorophyll (p. 506)
acellular slime mold - slime mold that passes through a stage in which its cells fuse to form large cells with many nuclei (p.516)
acetylcholine - neurotransmitter that diffuses across a synapse and produces an impulse in the cell membrane of a muscle cell (p. 929)
acid - compound that forms hydrogen ions (H+) in solution (p.43)