Which of the following adaptions helps birds fly a: they have more fat than most animals so they can fly for long distances
b: they have hollow bones so they are lighter
c they have a smaller blood vessel so
their heart have to work less in a flight
d: the largest stomach so that they can absorb food faster

The carbon cycle is best defined as a process in which a. carbon changes from inorganic forms to organic forms and back b. carbon is changed into other elements such as oxygen or nitrogen c. carbon is continually created from the sun’s energy by plants d. carbon is consumed and regenerated from other elements such as oxygen and nitrogen