Measuring the volume of an object you are finding the amount of three dimensional space the object occupies
A food chain shows a single connected path of energy flow through an ecosystem. It shows the different levels of eating in an ecosystem. Both a good web and a good chain include a number of organisms including both producers and consumers. A food chain is very simple while a food web is complex and consists of a number of food chains. In a food chain each organism has only one consumer or producer.
C. Decreased death rate is the answer
