Why don’t most other types of bacteria produce ulcers?

Explain the importance of producers, primary consumers, secondary consumers and decomposers in an ecosystem.

Long term exposure to waves can cause sunburns and skin cancer.

Food webs - transferring energy and matter from one level to another. here you see four food webs. one or more are incorrect. which food web(s) show the correct sequence of organisms, from start to top level consumer? a) a b) d c) c d) a and d