A it can be lost during an organisms lifetime
Answer: B
Explanation: A closed system can be defined as a system that does not allow for an exchange of matter with its surroundings.
An estuary where fresh water and ocean water mix is not a good example of a closed system because fresh water and ocean water mix out in the open and matter is exchanged.
A living single-called organism such as phytoplankton does not constitute as a closed system because in order for the phytoplankton to be considered alive it needs to interact with its surroundings i.e light from the sun so photosynthesis (converting light energy into chemical energy to be used by organism) can occur. This also happens out in the open
A river that flows into the ocean does not fit into the closed system definition. This is because a river that flows into the ocean allows for itself (matter) to mix with that of the ocean in an open space (rivermouth).
Therefore option B is the answer because it fits the definition. A chemical reaction within the deep ocean organisms that allows them to glow happens within (inside) the organism, making this system closed, hence there is no exchange of matter with surroundings.
Answer:
Both options are true.
Explanation:
The cylindrical epithelium is a simple epithelium, which is characterized by having a cell layer, where all the cells are supported on the basement membrane, and its nucleus has reverse polarization in relation to the rest of the cells of our body, that is, they are found in a not very common position.
Simple cylindrical epithelia are found in areas of absorption or assimilation and exchange of gases or nutrients, since this shape is what allows them optimal diffusion through the epithelium, an example of the tissues in which this cellular architecture is found. They are the intestinal tract and the respiratory tract.
In the case of pseudostratified epithelium, it is very similar in function to the cylindrical one, with the difference that it gives a multilayered appearance, that is, its cells are stacked one from the other, giving the appearance of more than one epithelial layer as the stratified epithelium of our epithelial organ, but nevertheless it is not like that, there are many cells of irregular shape with a support in the basal one, that is why it is a single layer.
This last epithelium is also found in the airways in large numbers.
