Question

(i) Why do ventricles have thicker muscular walls than atria?
(ii) What are peristaltic movements?
(iii) “Stomata remain closed in desert plants during day time”. How do they do photosynthesis?

Answer 1

1. because they have to pump oxygenated blood to all the parts of human body and deoxygenated blood to the lungs.
2. Peristalsis, involuntary movements of the longitudinal and circular muscles, primarily in the digestive tract but occasionally in other hollow tubes of the body, that occur in progressive wavelike contractions. Peristaltic waves occur in the esophagus, stomach, and intestines.
 3. They perform Crassulacean Metabolism  This metabolism was first observed in Crassulacean plants. At night, the stomata are open and take in carbon dioxide.then , it is stored in an intermediate form and is used to synthesize glucose during day-time.

Answer 2

HEYA!!!!!!!

HERE IS THE ANSWER TO YOUR QUESTION......


(i) Since ventricles have to pump blood into various organs, they have thicker muscular walls than atria do.

(ii) The lining of alimentary canal has muscles that contract rhythmically in order to push the food forward. These are peristaltic movements.

(iii) In desert plant, stomata open at night and absorb CO2, and store it as an intermediate compound, that is converted into carbohydrates during daytime.


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