The endocrine system releases chemicals that enter the bloodstream for distribution throughout the body. releases hormones that alter the metabolic activities of many different tissues and organs simultaneously. produces effects that can last for hours, days, and even longer. functions to control ongoing metabolic processes. all of the above

The images show two species of tree frogs in a particular region. the gray tree frogs are adapted to the trees of the woodlands, while the green tree frogs can survive in woodlands or grasslands. the gray frog was abundant in the woodlands. because of climatic changes, most of the trees in the region died, and the woodlands changed to grasslands. in such a case, the . the gray tree frog is closely related to the green tree frog genetically, but they have different mating calls. this suggests that speciation occurred because of .