Answer: The independent variable is the one that is changed/controlled by the scientist. To ensure a fair test, a good experiment has only one independent variable. ... Experiments also have constants or controlled variables. Controlled variables are things that a scientist wants to remain the same throughout the experiment.
Explanation:
It's true cause plants make oxygen that all animals breathe.
Answer:
By exercising and eating a good diet
Explanation:
Cephalochordata is the subphylum that retains all chordate characteristics, even in the adult forms.