Trees are a storage for excess carbon and if they are removed put carbon back into the atmosphere. The ocean also takes in carbon but the excess carbon causes acidification in the water. Identify and explain another way that excess carbon could be stored.

For review 1. in terms of which government is sovereign, differentiate among a unitary system, a confed- eral system, and a federal system of government. 2. to which level of government does the constitution distribute the enumerated po implied powers? concurrent powers? reserved powers? provide several power. 3. what matters fall within the scope of state sovereignty? differentiate among dual federalism, cooperative federalism, centralized federalism, and conflicted federalism. how does the national government use grants-in-aid, mandates, and preemption to direct the policy of state and local governments? 6. what do we mean by intergovernmental relations? why is the term a good description of u.s. federalism today? 7. list several advantages and several disadvantages of a federal system.