Acclimatization - short-term, reversible responses to environmental fluctuations // phenotypic change in an individual in response to short-term changes in the natural environment. The ability to acclimatize is itself an adaptation. As an individual develops, the embryonic tissues give rise to four adult tissue types: 1. Connective tissue loose connective tissue - fibrous proteins in a soft matrix; serves as a packing material b/w organs or padding under the skin (ex: reticular connective tissue in lymphoid organs such as the spleen and bone marrow/ adipose tissue or fat tissue are loose connective tissues made up of cells suspended in a matrix of fibers and fluid) dense connective tissue - found in tendons and ligaments that connect muscles, bones,