What is the need for a system of control and coordination in an organism?
Control and coordination is important for the survival of living organisms. Control comes under endocrine system by sending chemical messengers called hormones and nervous system composed of neurons which controls our body by sending electrical signals called nerve impulses.
Coordination is working together of various parts of body of multicellular living organisms in a sequence to inhance the functions of each other. Control and coordination is important in organisms so that they can do voluntary, involuntary actions in their biological rhythm cycle (24 hour cycle or sleep-awake cycle).
Draw the structure of a neuron and explain its function.
Which signals will get disrupted in case of a spinal cord injury?
How does chemical coordination take place in animals?
Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.
Why is the use of iodised salt advisable?
The brain is responsible for
(a) thinking.
(b) regulating the heart beat.
(c) balancing the body.
(d) all of the above.
How do we detect the smell of an agarbatti (incense stick)?
How do auxins promote the growth of a tendril around a support?
How does our body respond when adrenaline is secreted into the blood?
Which part of the brain maintains posture and equilibrium of the body?
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
What is a good source of energy?
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
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 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?
What is a neutralisation reaction? Give two examples.
Why are human beings who look so different from each other in terms of size, colour and looks said to belong to the same species?
What are the differences between the transport of materials in xylem and phloem?
Why do ionic compounds have high melting points?
You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.
What is a balanced chemical equation? Why should chemical equations be balanced?
If all the waste we generate is biodegradable, will this have no impact on the environment?
How many structural isomers can you draw for pentane?
Most of the sources of energy we use represent stored solar energy. Which of the following is not ultimately derived from the Sun’s energy?
(a) geothermal energy (b) wind energy
(c) nuclear energy (d) bio-mass.
Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?