There are plenty of plants producing oxygen by photosynthesis.
Also, human's only use 5% of the oxygen in the air in respiration, there is 21% in the air.
Lymphatic system & Immune system are worked by B- & T- Cells respectively. They are the antibodies which works together. When some foreign substance invade a body, then lymphatic system alters the Immune system which destroys it by an appropriate action!
Hope this helps!
Answer:
Whenever any experiment is performed then there are two variable in the experiment. These variables are dependent variable and independent variable.
The experimenter is able to change the independent variable in the experiment based on that the dependent variable is recorder.
If finding out the results of the experiments then it is said that the variable which is tested is dependent.
The change in the independent variable causes change in the dependent variable.
