Q 1. Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans.
Answer: All cells of a unicellular organism are directly in contact with the environment and they do not require special organs for any work. In multicellular organisms, all the cells are not in direct contact with the surrounding environment due to the complex structure of the body.
Therefore, simple diffusion will not meet the oxygen requirement of all the cells.
Q 2. What criteria do we use to decide whether something is alive?
Answer: all living structures are made up of molecules that must keep repairing and maintaining their structures. They must be capable of moving molecules around, all the time. So, molecular movement is necessary to identify whether something is alive. Movements may be locomotion, chewing, breathing, growth
Q 3. What are the outside raw materials used by an organism?
Answer: There are mainly three types of raw materials that are used by an organism.
FOOD- Food as a source of supplying energy and materials.
OXYGEN- Oxygen for the break down of the food to obtain energy.
WATER- for proper digestion of food and other functions inside the body.
In case of plants they obtain raw materials like CO², H²O and minerals.
Q 4. What processes would you consider essential for maintaining life?
Answer- There are various life processes which are essential for maintaining life. Some of them are :-