Nonliving environmental factors.
Method used to determine fossil age by radioactivity.
Neurotransmitter produced by the terminal branched of nerve cell.
Compound forms hydrogen ions lacking a electron when dissolved in water; pH less than seven.
Gene mutation; chromosome mutation.
Cellular respiration that requires oxygen and takes place in the mitochondria.
One of two kinds of genes for a trait.
Tine air sacs.
Organic compound that is the building block of proteins.
Cellular respiration that does not require oxygen and takes place in the cytoplasm outside the mitochondria.
Structures that are similar in function but dissimilar in construction and evolutionary development.
Part of the stamen of a flower and the producer of pollen grains.
Phylum in kingdom Plantae that includes flowering plants that usually reproduce by seeds hidden inside fruits.
Substance produced by some bacteria or fungi that can destroy bacteria but not viruses.
Protein in the blood that can help fight disease by destroying harmful substances such as antigens, bacteria and viruses.
Side of tRNA that is complementary to the codon on an mRNA molecule.
Domain that includes prokaryotic unicellular organisms with cell walls lacking peptidoglycan.