absorption achromatic adaptation aerobic algae alimentary allergy amoeba amphibian analogue anatomy ancestor antibody appendage aquatic arboreal asexual assimilation atrophy auditory backbone bacteria balance barrier benign biology biome bisect botany branch breathe carnivorous catalyst cavity cell chlorophyll cholesterol chromatic chromosome cilia classification cohesive collagen communicable community contraction control convolution coronary cyclic darwin deciduous decomposition dermis develop dichotomous dietary differentiation diffusion digestion dinosaur discipline displacement division dna dominant dormant ecology ecosystem ectoplasm edema embryo endangered endemic endoskeleton endothermic energy environment enzyme epidermis erosion essential estrogen evolution exoskeleton exothermic extermination extinct factor feedback fertilization fetus fibrillation filament fish fission flower food chain fossil function gamete gaseous gastrin genetics genome genus germ gestation gills grafting greenhouse effect growth habitat hemoglobin herbivore heredity heterogeneous hibernation hierarchy homogeneous hormone horticulture host human hybrid immunity inclusion incubate ingestion inherited traits inoculate inquiry insoluble instinct insulate insulin interdependent invertebrate involuntary isolate isotope juncture kinesthesia kingdom latitude leaf life cycle linkage living luminescent lymph malignant mammal marine meiosis membrane memory metabolism microbiology microscope migration mildew molt muscle mutation mutualism natural nerve neuron nitrogen nonliving nucleus omnivorous optic order organs osmosis ossification oviparous oxidation paleontologist parasite parasympathetic pathogen permeable photosynthesis plankton plasma platelet pollen pollution portion predator preserve pressure producer protein protoplasm pulmonary pyramid quest question radial receptor recessive recycling reflex regeneration regulate replicate repress reptile residual resource respiration restriction rh factor root scope secrete seed sensor shelter skeleton skin solar spatial species specimen statistics stimulus stress structure symbiosis symmetry synapse system taste taxonomy tendril terrestrial tissue tolerance toxin transformation transpiration tundra turgid unsaturated vacuole variation ventilate vertebrate viable virus vital vitamin viviparous volume voluntary waste weather chromosome chromosome zone zoology