Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
Diffusion is a slow process and is insufficient to meet the requirements of the multi- cellular organisms like humans. Human beings are the multi- cellular organisms and have complex body structures. All the body cells do not contain direct contact with the environment, so they need the oxygen and oxygen requirement cannot fulfil by the diffusion process.
So, in the multi- cellular organisms like human beings they have special types of tissues and the organs which helps them to meet the oxygen requirement of the body.
How is the amount of urine produced regulated?
What criteria do we use to decide whether something is alive?
What are the different ways in which glucose is oxidised to provide energy in various organisms?
The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
(a) cytoplasm. (c) chloroplast.
(b) mitochondria. (d) nucleus.
What are the differences between autotrophic nutrition and heterotrophic nutrition?
What are outside raw materials used for by an organism?
What would be the consequences of a deficiency of haemoglobin in our bodies?
What are the components of the transport system in highly organised plants?
What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Describe the structure and functioning of nephrons.
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
What is a good source of energy?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
What changes can you make in your habits to become more environment-friendly?
What is the difference between a reflex action and walking?
What is the importance of DNA copying in reproduction?
If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
Why should a magnesium ribbon be cleared before burning in air?
Define the principal focus of a concave mirror.
You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?
Why should curd and sour substances not be kept in brass and copper vessels?
Let the resistance of an electrical component remains constant while the potential difference across the two ends of the component decreases to half of its former value. What change will occur in the current through it?
While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid?
Explain the underlying principle and working of an electric generator by drawing a labelled diagram. What is the function of brushes?
On what factors does the resistance of a conductor depend?
How much energy is given to each coulomb of charge passing through a 6 V battery?
Name a device that helps to maintain a potential difference across a conductor.
Would you be able to check if water is hard by using a detergent?
What is hydrogenation? What is its industrial application?
What would be the advantages of exploiting resources with short-term aims?