Class 9 Biology
Class 9 Biology
Class 9 Biology
MCQs:
True or False:
351. Meristematic cells have a prominent nucleus and dense cytoplasm but they lack vacuole.
R: Meristamatic tissue cells are continuously dividing and they have prominent nucleus and a dese
cytoplasm. Since they are diving rigorously they need not store food or waste products hence they
lack vacuoles.
352. Intercellular spaces are absent in sclerenchymatous tissues.
R: Cellwall of sclerenchyma are lignified and are packed densely to protect the plant and to give
mechanical strength hence intercellular spaces are absent in sclerenchymatous tissues.
353. We get a crunchy and granular feeling, when we chew pear fruit.
R: In pear fruit sclerenchyma cells are called stone cells. They are small, thick and hard. Because of
this We get a crunchy and granular feeling, when we chew pear fruit.
354. Branches of a tree move and bend freely in high wind velocity.
R: Junction of the tree branch composed of collenchyma cells which provide rigidity and flexibility
to the branches. Hence Branches of a tree move and bend freely in high wind velocity.
355. It is difficult to pull out the husk of a coconut tree.
R: Husk of coconut tree is sclerenchyma which is hard. Hence it is difficult to pull out the husk of a
coconut tree.
356. Fertile soil has a lot of humus.
R: Humus is the organic matter contained in soil, formed by the decomposition of leaves and other
plant material by soil microorganisms. It provides nutrients to the plants and increases the ability of
soil to retain water. Now, fertile soil contains lots of microorganisms, which decompose the dead
animal and plant material and thus add humus to the fertile soil.
357. Lichens help in the formation of soil.
R: Lichens are a symbiosis of fungi and green algae living and growing on rocks where they
help in the breakdown of the rocks’ surface by releasing some chemicals. These chemicals produce
pores and crevices and thus help in weathering of rocks and formation of soil.
358. During summer, walking around a lake or a river, will give you relief from heat.
R: During summer days, the land near the lake or river gets heated up quickly but the water in lake
or river remains cool. The wind above the land heats up, and hot air, being lighter, rises up, and the
cool air above the lake/river flows to take its place causing a cool breeze to blow from lake/ river to
land hence reduces the heat in the adjoining land area.
359. Dust is the major pollutant.
R: Dust is a common air pollutant generated by many different sources and activities like natural
erosion of soil, Pollen, microscopic organisms, concrete crushing, cement batching and road stone
plants. Smaller dust particles are light enough to be carried by air which when inhaled penetrate
deeply into the lungs and even the ultra fine particles can be absorbed directly into the blood stream
causing the respiratory problems like coughing, sneezing, asthma attacks, etc.
360. Consumption of fatty food causes thrombosis.
R: A diet high in saturated fats -- derived mainly from meat and dairy products -- can lead to high
cholesterol levels in the blood, which can contribute to fatty buildup, called plaque, in the body's
blood vessels. The obstructions can block blood flow and trigger a heart attack or stroke.
361. Bryophytes are called “amphibians of the plant kingdom.
R: Amphibians are the organisms that live on both land and in water. Bryophytes are called
amphibians of the plant kingdom because these plants live in soil but they need water for asexual
reproduction. ... The sperms of bryophytes swim through water to the eggs with the help of their
flagella.
362. Spiders and scorpions are very different from each other but are placed in the same phylum –
Arthropoda.
R: They have jointed appendages. They have open circulatory system.
363. Platyhelminths and Nematodes possess a Pseudocoelom.
R: Platyhelminthes are acoelomate and not pseudocoelomate while nematodes are
pseudocoelomate, as they have a very simple body structure and not many organs are there so they
have an incompletely developed coelom.
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