The Brahman cattle have good resistance to high temperature, but its meat is poor and tough to eat. The English shorthorn cattle, on the other hand, have good meat, but poor resistance to high temperatures. Farmers formed the Santa Gertrudis cattle by breeding Brahmans with English shorthorns. This new type of cattle has good meat and resistance to high temperatures. Which of the following best describes the process used to produce the Santa Gertrudis cattle? A.
genetic engineering

B.
inbreeding

C.
natural selection

D.
selective breeding

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.