The difference between bacteria and viruses that show bacteria are living and not viruses is that viruses, unlike bacteria, lack what is considered a living organism. For Example, viruses cannot reproduce without the help of a host, and don't use the normal way of cell-division for replication. Unlike bacteria, which can reproduce without the aid of a host.
So basically viruses don't have what it need to be a living organism, like reproducing without and host and aren't in the norm for cell-division for replication.
Answer:
The correct answer is A) Biochemical test
Explanation:
In microbiology biochemical test is used to examine the metabolic activities performed by bacteria to identify that microorganism. So in biochemical test enzymatic reaction of cell is usually investigated because there is difference in enzymatic activity of different species of bacteria.
For example, catalase test that is used to differentiate between catalase-positive and catalase-negative bacteria is an example of biochemical test. Catalase-positive bacteria have the catalase enzyme that breaks hydrogen peroxide into water and oxygen which is confirmed by bubbles that appear on glass slide.
Catalase negative bacteria do not form bubbles when they are put in hydrogen peroxide which shows that they lack catalase enzyme. So the right answer is A.
This question is incomplete as the specific food chain is not provided. In general, a food chain will have a primary producer at the base of the chain. This is an organism that is able to utilise a form of energy to convert carbon dioxide in the atmosphere to a carbohydrate. For terrestrial food chains, these are typically plants, who by utilising the energy from the sun, are able to convert carbon dioxide to carbohydrates. The subsequent level in the food chain may be a primary consumer, typically herbivores, that consume plant matter. Subsequent links in the chain would typically be secondary consumers, who would be carnivores, omnivores or decomposers. Carnivores would typically be predators and would be at the apex of the food chain. Energy is lost from one link to the subsequent link in the food chain, through basic respiration and inefficient energy transfer from one link to another. This explains why more resources (land, water and air) are required to grow meat rather than plant matter. More of the sun's energy is available within the lower trophic levels in a food chain, before much of it is lost as energy moves up the food chain. An easy example to illustrate this is that much of the livestock raised in the USA is fed grain. If people rather ate the grain than the livestock, they could obtain all their required energy from a smaller amount of grain then would be needed to raise the meat they require.
The answer is A. Excretion I hope this helps