Answer:
a
Explanation:
Remember, a biotic factors are those that are living (having life in them), while the abiotic factors are not living organisms.
Oxygen is in the category of biotic and it interacts with the atmosphere (space) which is abiotic.
The three observations that could help an individual in distinguising whether the organism is a fish or not is that it should live under water as fish can't survive without water, another thing is that it should laid eggs when it comes to giving birth because when it does not lay eggs but produces a living organism normally without an egg, it is considered to be a mammal and lastly, the appearance it possess such as having gils or fins.
