CBSE 2024-25 Competency-Based Questions With Answers: Well, Assessment is an integral part of learning that helps to build the knowledge that students acquire throughout the course. The assessment can be of various types and all of them are designed to assess the understanding of the students on a particular subject or a topic.
The Central Board of Secondary Education has made available the competency-based questions for the academic year 2024-25. In this article, we will be providing the students with CBSE Class 12 Biology Chapter 4 Environmental Issues competency-based questions for the 2025 examination.
Additionally, a free PDF of Class 12 Chapter 4 Environmental Issues competency-based questions is also provided for the students with the given link.
CBSE Class 12 Biology Chapter 4 Environmental Issues Competency-Based Questions
Free Response Question / Subjective Question
1. In a research paper titled "Ecological Risk of DDT - A Case Study of Biomagnification Causing Extinction Risk of Herring Gull in Long Island" (Nakamaru et al, 2001), it was cited that the use of DDT causes immense risks of extinction of a bird named Herring Gull. There are severe implications of this.
(a) The Herring Gull is a top predator in the food pyramid of the area. How will its extinction impact the food chain?
State ONE reason that can bio-magnification cause the extinction of birds like the Herring Gull.
2. (a) Recycling of e-waste is one of the most popular methods of e-waste management in developing countries. It benefits a sizeable proportion of the population by employing in such countries. What can be one of the biggest disadvantages of these recycling efforts?
Incineration, as a process of e-waste management, can destroy organic constituents in e-waste. What is the main advantage of using incineration in a landfill?
3. Impurities in domestic sewage account for 0.1% of the total wastewater. Such impurities include:
A: suspended solids like sand, silt and clay
B: colloidal material like faecal matter, bacteria
C: dissolved materials like nutrients (nitrates, ammonia, phosphate, sodium, calcium etc).
As a project manager for the treatment of domestic sewage in a town, Shivam thought of recycling the sewage water into other processes in the area.
(a) How can Shivam remove the suspended solids from the sewage water?
(b) How can the colloidal impurities be used in any other process in the town?
(c) If domestic sewage is allowed to enter a pond or a lake without being treated, what can be ONE impact it has on the quality of water in the water body?
Answers
Answer 1
(a) 0.5 marks for each correct answer:
- increase in other predators, carnivores and herbivores in the area
- imbalance in the availability of food
(b) 1 mark each for mentioning any one of the following:
- decrease in fertility
- early breakage of eggshells
- thinning of eggshells
Answer 2
(a) exposes workers to hazardous and toxic substances during manual participation
(b) reduces volume of the waste
Answer 3
(a) 1 mark for any correct answer such as:
- sedimentation
- filtration
(b) in agricultural fields as organic manure
(c) 1 mark for mentioning any one of the following:
- increase of BOD
- Eutrophication
These were the questions along with answers for CBSE Class 12 Biology Chapter 4 Environmental Issues. We are also providing the free link below to download the PDF for CBSE Class 12 Biology Chapter 4 Environmental Issues competency-based questions.
CHECK: CBSE Class 12 Biology Chapter 4 Environmental Issues Competency-Based Questions
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