Keystone 1. occur only in intertidal zones 2. play an unusually important role in determining the species composition in a habitat 3. can be removed from a habitat without any impact on the remaining species in the community 4. are primary producers and therefore usually are plants 5. are more expendable than commensal species, from a conservation perspective

Which of the layers of the earth has the following three characteristics? i. it is made of molten rock. ii. it has currents that are constantly moving. iii. earth’s plates float on top of its currents.

In a constitutional monarchy, the king or queen a. is a symbol of the nation b. runs for office c. controls the legislative branch d. has absolute control

During metamorphic processes, increased pressure and temperature can affect the of minerals in rock. rocks subjected to very high pressure are typically than others because mineral grains are squeezed together, and the atoms are more closely packed. during metamorphic processes, water facilitates the transfer of ions between and within minerals, which can the rate at which metamorphic reactions take place. the growth of new minerals within a rock during metamorphism has been estimated to be about per million years. metamorphism is commonly associated with convergent plate boundaries, where two plates move toward each other. during contact metamorphism, a large intrusion will contain thermal energy and will cool much more slowly than a small one. metamorphosed sandstone is known as the metamorphic rock made from metamorphosed shale, was once used to make blackboards for classrooms