The RNA world hypothesis states that the earlier life-forms had relied only on RNA (Ribonucleic Acid) for the purpose of catalyzing the chemical reactions, and storing the genetic information. This hypothesis was proposed by Leslie Orgel, Carl Woese, and Francis Crick.
This hypothesis states that long before the living forms evolved to use DNA as the genetic storage material, the RNA molecules served the purpose of both storing the genetic information and carrying out catalysis, but because of its instability, DNA evolved.
Hence, the answer is RNA world hypothesis.
A virus can only reproduce itself if it takes over host cells!
For staining flagella of bacteria use actively motile organisms 20 to 24 hours old, allow to diffuse in sterile water 20 to 30 minutes, transfer droplets of the suspension to clean slides and let evaporate without spreading. Then treat 2 to 4 minutes with the following mordant: tannic acid 10 or 20%, 50 cc.; ferric chloride 5%, 10 to 15 cc.; carbol fuchsin (Ziehl-Nielson), 5 cc.; hydrogen peroxide 3%, 6 to 8 cc. Wash and stain 2 to 3 minutes with a mixture of basic fuchsin, saturated alcoholic, 10 cc.; anilin oil (1 part) and 95% alcohol (3 parts) mixed, 5 cc.; distilled water, 30 cc.; acetic acid, 4%, 1 cc. Wash thoroly with water.
I have encountered this question before, and the given diagram shows no producers. Moreover, it consists of pictures of five organisms, with no relationship being shown between them. Therefore, in order to make the model more accurate, Maria should add B. The sun and arrows to show the flow of energy.
The right option is; B) are not composed of cells.
The single, MOST important reason why viruses are classified as non-living is that they are not composed of cells. The cell is the basic unit of structure and function in organisms. All living organisms are composed of one or more cells (according to the cell theory) and viruses do not have cells. Therefore, many scientists classify viruses as non-living.
Viruses are non-cellular microscopic infectious organism that are composed of two main parts; nucleic acid (DNA or RNA) and a protein coat that protects the nucleic acid. Viruses require a living cell (host) to reproduce and usually cause disease in the host organism.
