D. As salt water in the oceans.
A facultative parasite refers to a species, which may resort to parasitic activity, but is not completely dependent on any host for finishing its life cycle. Therefore, the growth of Armillaria fungi inside a tree's roots, making the tree to rot, but will survive even if the tree dies, is an example of facultative parasitism.
An obligate parasite refers to a parasitic species, which cannot finish its life-cycle in the absence of a suitable host. Therefore, rickettsia bacteria's tendency to surviving only in a eukaryotic cell is an example of obligate parasitism.
A long-term symbiosis or biological association in which members of one species attain benefits while those of the other species is neither harmed nor are benefited is known as commensalism. Hence, a pseudoscorpion, a kind of arthropod hiding under the wings of beetle for protection and transportation, however, it does not affect the beetle is an example of commensalism.
Predation refers to a biological association, where one species, the predator, kills and consumes another species, known as prey. A freshwater amoeba feeds on bacteria in the water is an example of predator and prey.
Because they can make a baby with their oranism
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.