Answer:
a. commensalism is the correct answer.
Explanation:
By growing on the trunk or branch of a tree, a lichen gains height and exposure to sunlight for photosynthesis. The tree is not harmed by the lichen but does not benefit either. The relationship between the lichen and the tree is commensalism.
Commensalism is a relationship between two organisms where one organism gets benefits from other organisms without causing any harm or any damage from the relation as it one side symbiotic relation.
In this, we can see lichen is getting benefits from the tree.
for example, lichen is getting following benefits from the tree such as ( a lichen gains height and exposure to sunlight for photosynthesis.) and they are causing any harm to tree neither any benefits so this is a one-side symbiotic relation and thus the relationship is an example of commensalism.
Answer:
A hypothesis is a possible explanation for a set of observations or an answer to a scientific question. A hypothesis must be testable and measurable. This means that researchers must be able to carry out investi- gations and gather evidence that will either support or disprove the hypothesis.
Explanation: