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प्रश्न
Briefly describe the following:
Angina Pectoris
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उत्तर
- When enough oxygen does not reach the heart muscles, angina pectoris develops, causing chest pain and discomfort.
- Angina pectoris is the pain in the chest. It results from a reduction in blood supply to cardiac muscle due to narrowed and hardened coronary arteries.
- Angina pectoris often occurs during exertion, when the heart demands more oxygen and narrowed blood vessels cannot supply. It disappears with rest.
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संबंधित प्रश्न
What causes the opening and closing of guard cells of stomata during transpiration?
Define the term Transpiration stream
Name the process by which water loss takes place through the leaves.
Given below is a diagrammatic sketch (surface view) of a stomatal apparatus from a dicot leaf.
(a) Label the parts numbers 1-3
(b) Is this state, open or closed?
(c) Is this stoma, of a dicot leaf or a monocot leaf?
(d) Redraw a sketch of the stomatal apparatus in the state opposite to the one shown here.
Give a reason.
What happens to the movement of the air-bubble if the apparatus shown above is kept in sunlight.
Comment on the following statement:
A well-watered potted plant shows wilting of leaves on a hot sunny day.
An apparatus as shown below was set up to investigate a physiological process in plants. The setup was kept in sunlight for two hours. Droplets of water were then seen inside the bell jar. Answer the questions that follow:
Name the process being studied.
Describe an experiment to prove that transpiration occurs more from the undersurface of dorsiventral leaves.
Explain the term:
Transpiration
What causes the opening and closing of guard cells of stomata during transpiration?
Transpiration is a necessary evil in plants. Explain.
Why is transpiration called a necessary evil?
Describe briefly the three physical properties of water which helps in ascent of water in xylem.
Will the ascent of sap be possible without the cohesion and adhesion of the water molecules? Explain.
Why is transpiration less in the still wind?
