Page #95 Question 1 Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans ? Answer: In multicellular organisms like humans, all the body cells are not in direct contact with the surrounding environment. Therefore, every cell of the body will not get oxygen as per need by the process of diffusion from the environment. Therefore diffusion is insufficient to meet the oxygen requirements of multicellular organisms. Question 2 What criteria do we use to decide whether something is alive ? Answer: The main criteria used to decide whether something is alive are breathing and respiration. However, living beings also show growth and movement. Question 3 What are outside raw materials used by an organism ? Answer: Any organism uses organic molecules as raw material. Heteroptrophs use food and autotrophs use carbon dioxide, minerals, water and all organisms use oxygen (for respiration) as raw materials. Question 4 What processes would you consi...