enhancing respiratory and circulatory efficiency; depending on free oxygen or air
anaerobic
living or active in the absence of free oxygen
asexual reproduction
reproduction without the fusion of gametes
asteroids
any of numerous small celestial bodies that revolve around the sun
carbon cycle
a thermonuclear reaction in the interior of stars; the organic circulation of carbon from the atmosphere into organisms and back again
cell organelles
specialized part of a cell; analogous to an organ
chromosome
a structure in the cell nucleus that contains DNA
density
thickness; quantity of something per unit measure, especially per unit length, area, or volume
diffusion
act of dispersing or diffusing something
gene
a segment of DNA that is involved in producing a polypeptide chain
heredity
genetics; inheritance; genetic transmission of characteristics from parent to offspring
homeostasis
metabolic equilibrium actively maintained by several complex biological mechanisms that operate via the autonomic nervous system to offset disrupting changes
meiosis
cell division that produces reproductive cells in sexually reproducing organisms
mitosis
cell division in which the nucleus divides into nuclei containing the same number of chromosomes
organ
natural part or structure in animal or plant, capable of performing some special action
organisms
discrete and complete living thing, such as animal, plant, fungus or microorganism
osmosis
diffusion of molecules through a semipermeable membrane from a place of higher concentration to a place of lower concentration until the concentration on both sides is equal
photosynthesis
chemical combination brought about by the action of light
qualitative change
changes in kind or type
quantitative change
an alteration in the number
respiration
breathing; process of inhaling and exhaling; oxidative process occurring within living cells
sexual reproduction
reproduction involving the union or fusion of a male and a female gamete
species diversity
the variety of species in a given region or area
tissue
groups of cells that make particular parts of the body; soft thin paper
transpiration
the process of giving off or exhaling water vapor through the skin or mucous membranes; the emission of water vapor from the leaves of plants
transport
carry from one place to another; carry away; deport