What is the role of the brain in reflex action?
Reflex action is a rapid or quick response to stimulus (involuntary mechanism) because of lower number of synapses. so, the organism don't have enough time to think. The path of an impulse to travel only in one direction (reflex arc) as afferent to efferent neurons and this information also reaches the brain, where the brain records this event and stores it as a memory.
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 advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Which of the following lenses would you prefer to use while reading small letters found in a dictionary?
(a) A convex lens of focal length 50 cm.
(b) A concave lens of focal length 50 cm.
(c) A convex lens of focal length 5 cm.
(d) A concave lens of focal length 5 cm.
Find out about the traditional systems of water harvesting/management in your region.
Consider a circular loop of wire lying in the plane of the table. Let the current pass through the loop clockwise. Apply the right-hand rule to find out the direction of the magnetic field inside and outside the loop.
Why do we prefer a convex mirror as a rear-view mirror in vehicles?
Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?
Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows.
Metal | Iron(II) sulphate | Cooper(II) sulphate | Zinc sulphate | Silver nitrate |
A | No reaction | Displacement | ||
B | Displacement | No reaction | Displacement | |
C | No reaction | No reaction | No reaction | No reaction |
A study found that children with light-coloured eyes are likely to have parents with light-coloured eyes. On this basis, can we say anything about whether the light eye colour trait is dominant or recessive? Why or why not?
Write equations for the reactions of
(i) iron with steam
(ii) calcium and potassium with water.
Why does menstruation occur?