<span>Bacteria are tiny. A typical bacterial cell is just a few micrometres across (a few thousandths of a millimetre). The structure of a bacterial cell is different to an animal or plant cell. For example, they do not have a nucleus but they may have a flagellum. This is a tail-like part of the cell that can spin, moving the cell along.A unicellular organism is a living thing that is just one cell. There are different types of unicellular organism, including:
bacteria
protozoa
unicellular fungi
You might be tempted to think that these organisms are very simple, but in fact they can be very complex. They have adaptations that make them very well suited for life in their environment.Protozoa are unicellular organisms that live in water or in damp places. The amoeba is an example of one. Although it is just one cell, it has adaptations that let it behave a bit like an animal:
it produces pseudopodia (false feet) that let it move about
its pseudopodia can surround food and take it inside the cell
contractile vacuoles appear inside the cell, then merge with the surface to remove waste
You may be familiar with fungi from seeing mushrooms and toadstools. Yeast are unicellular fungi. They are used by brewers and wine-makers because they convert sugar into alcohol, and by bakers because they can produce carbon dioxide to make bread to rise.
Yeast have a cell wall, like plant cells, but no chloroplasts. This means they have to absorb sugars for their nutrition, rather than being able to make their own food by photosynthesis
Yeast can reproduce by producing a bud. The bud grows until it is large enough to split from the parent cell as a new yeast cell.</span>
Muscle cells, also known as myocytes, contain numerous amounts of mitochondria inside of their cytoplasm. Mitochondria are organelles that are popularly known as the powerhouse of the cell because they function to process different biochemicals (such as glucose, oxygen, etc) and produce essentially Adenosine Triphosphate (ATP). Kreb's Cycle in particular talks about energy production, and the mitochondria is one of the main units where this cycle happens. You can think of ATP as the currency of the body in terms of energy. The more ATP one has, the more energy there is available for use by the different systems of the body. Muscles in particular have high demand for ATP.
Answer:
D
Explanation:
The correct answer would be that the origin of all cells can be traced to previous or pre-existing cells.
According to the cell theory which is made up of three parts;
- <em>The cell represents the basic unit of all life.</em>
- <em>All living organisms are made up of cells.</em>
- <em>Cells do not arise spontaneously, but only from pre-existing cells.</em>
Hence, the discovery that the origin of all cells is traceable to previously existing cells supports the latter part of the cell theory.
The correct option is, therefore, D.
As there are no answer choices, I'm going to answer this just based off my knowledge
Analogous structures suggest convergent evolution because they have both evolved from a set of species but for different reasons and from different causes.
