Charcot-Marie-Tooth is a muscular wasting disease that affects 1 in 2,500 people. Researchers have discovered that this occurs when a large gene on the short arm (p-arm) of chromosome number 17 makes a new copy of itself. What kind of chromosomal mutation is this?

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".

bradykinin is a physiologically and pharmacologically active peptide of the kinin group of proteins, consisting of nine amino acids.

only about ten percent of the energy at one trophic level is passed on to organisms at the next trophic level. the remainder of the energy is used in life processes or lost as heat.