Nutrient Cycling is a Environment concept from the MPSC syllabus, tested in 5 past MPSC questions across 4 exam years between 2013 and 2025. Below are those real questions with their correct answers and explanations, plus the concepts worth being comfortable with first.
bacteria into humus. The process involved in the early stages of this transformation depends throughout on oxidation : afterwards it takes place in the absence of air. The process is entirely sanitary. There is no nuisance of any kind - no smell, no flies, no dustbins, no incinerators, no artificial sewage system, no water - borne diseases, no town councils, and no rats. On the contrary, the forest affords a place for the ideal summer holiday with sufficient shade and an abundance of pure fresh air. All over the surface of the woods the conversion of vegetable and animal wastes into humus is never so rapid as during the holiday months - July to September.
The mineral matter needed by the trees and the undergrowth is obtained from the subsoil. This is collected in dilute solution in water by the deeper roots, which also help in anchoring the trees. Even in soils markedly deficient in phosphorus, trees have no difficulty in obtaining ample supplies of this element. Potash, phosphate, and other minerals are always collected in situ and carried by the transpiration current for use in the green leaves. Afterwards they are either used in growth or deposited on the floor of the forest in the form of vegetable waste being one of the constituents needed in the synthesis of humus. This humus is again utilized by the roots of the trees. Nature’s farming, as seen in the forest, is characterized by two things, a constant circulation of the mineral matter absorbed by the trees and a constant addition of new mineral matter from the vast reserves held in the subsoil.
खालीलपैकी कोणते विधान चुकीचे आहे ?
Which of the following statements is incorrect ?
(a)वनखते प्रक्रिया निरंतर चालू असते / Natural forest manuring goes on round the clock.
(b)पावसाळ्यात ती अतिशय शीघ्र असते / It is quicker during monsoons.
(c)वने येथे, उत्पादक, पुरवठादार व उपभोक्ता असतात / Forest acts therein as manufacturer, distributor and consumer.
(d)मानवाचा हस्तक्षेप त्यात नसतो / Man's interference therein is absent
1)(a)
2)(c)
3)(d)
4)वरील कोणतेही नाही / none of the above✓ Correct
All statements (a, b, c, d) regarding natural forest manuring and ecosystems are scientifically accurate, meaning none of them are incorrect.
मृत उत्पादकांच्या पेशीमधील जैविक संयुगांचे विघटन करण्याची प्रक्रिया म्हणजे __________.
The breakdown of organic compounds of cells from dead producer by the process known as __________.
(a)आत्मसात करणे (Assimilation)
(b)जैवर्धन (Biomagnification)
(c)संचयन (Accumulation)
(d)अपघटन (Decomposition)
1)अ फक्त
2)अ आणि ब फक्त
3)क फक्त
4)ड फक्त✓ Correct
Decomposition (अपघटन) is the biological process by which dead producers and consumers are broken down into simpler organic/inorganic compounds.
खालील पैकी कोणता घटक प्रवाल किटकांच्या वाढीला कारणीभूत आहे?
Which of the following factor is responsible for low coral growth?
1)सागर जलाचे अधोवहन / Downwelling of sea water
2)सागर जलाचे उर्ध्ववहन / Upwelling of sea water✓ Correct
3)सागर जलाचे तळप्रवाह / Under current of sea water
4)औष्णिकक्षारतामूलक प्रवाह / Thermohaline current
Upwelling brings cold, nutrient-rich deep water to the surface, which lowers temperatures and introduces excess nutrients/turbidity that hinder coral growth.
परपोषी जीवामधील, मुख्यतः सूक्ष्मजीव व बुरशी मृत पेशीद्रव्यातील क्लिष्ट संयुगे फोडून त्याचे सोप्या घटकात रूपांतर करतात जे इतर जीवांना उपयुक्त ठरतात त्या परपोषीजीवांना ________ म्हणतात. / Heterotrophic organisms, chiefly bacteria and fungi that breakdown the complex compounds of dead protoplasm and release simple usable substances for other organisms are :
1)स्वयंपोषी / Autotrophs
2)विघटक / Decomposers✓ Correct
3)भक्षक / Consumers
4)मीश्रहारी / Omnivorous
Heterotrophic organisms like bacteria and fungi that break down dead organic matter into simpler substances are known as decomposers or saprophytes.
bacteria into humus. The process involved in the early stages of this transformation depends throughout on oxidation : afterwards it takes place in the absence of air. The process is entirely sanitary. There is no nuisance of any kind - no smell, no flies, no dustbins, no incinerators, no artificial sewage system, no water - borne diseases, no town councils, and no rats. On the contrary, the forest affords a place for the ideal summer holiday with sufficient shade and an abundance of pure fresh air. All over the surface of the woods the conversion of vegetable and animal wastes into humus is never so rapid as during the holiday months - July to September.
The mineral matter needed by the trees and the undergrowth is obtained from the subsoil. This is collected in dilute solution in water by the deeper roots, which also help in anchoring the trees. Even in soils markedly deficient in phosphorus, trees have no difficulty in obtaining ample supplies of this element. Potash, phosphate, and other minerals are always collected in situ and carried by the transpiration current for use in the green leaves. Afterwards they are either used in growth or deposited on the floor of the forest in the form of vegetable waste being one of the constituents needed in the synthesis of humus. This humus is again utilized by the roots of the trees. Nature’s farming, as seen in the forest, is characterized by two things, a constant circulation of the mineral matter absorbed by the trees and a constant addition of new mineral matter from the vast reserves held in the subsoil.
खालील विधाने पहा :
आता सांगा :
Consider the following statements :
Now state whether
(a)पोटॅश व फॉस्फेट इतर ठिकाणाहून आणली जातात. / Potash and phosphate are brought from elsewhere
(b)त्यांचा उपयोग केवळ खत निर्मितीत होतो. / They are used only in the formation of humus.
1)दोन्ही विधाने बरोबर / Both are correct
2)दोन्ही विधाने चूक / Both are incorrect✓ Correct
3)(a) बरोबर तर (b) चूक / (a) is correct (b) is not
4)(b) बरोबर तर (a) चूक / (b) is correct (a) is not
In a natural forest ecosystem, potash and phosphate are derived from natural soil minerals and organic matter recycling, not imported from elsewhere (Statement a is false). They serve multiple physiological and structural roles in plants, not just humus formation (Statement b is false).