CBSE 12TH BIOLOGY - Online Test
Q1. The stage for counting of chromosome is
Answer : Option D
Explaination / Solution:
During cell division, chromosomes get condensed in shape. In metaphase stage of mitosis, the chromosomes are located at center of cell in linear fashion. It can be easily studied at this stage.
Q2. Which one of the following is not used in organic farming?
Answer : Option C
Explaination / Solution:
In organic farming snail is not used. Glomus is kind of fungi used in organic farming for maintaining fertility of soil. Earthworm the process of composting to form vermiform compost and Oscillatoria is an algae that fix the nitrogen.
Q3. Which of the following can be categorised as a biological pollutant
Answer : Option D
Explaination / Solution:
Mildew is thin white coating consisting of minute fungal hyphae growing on woods, leather or paper. It is a biological pollutant. Heavy metal, industry wastes and organophosphates are physical components.
Q4. Production of large scale recombinant products can be done in
Answer : Option B
Explaination / Solution:
Bioreactor is a large vessels in which large scale raw materials are biologically converted into specific products.
Bioreactor is used to produce large scale production.
Q5. Assertion: The earliest organisms that appeared on the earth were non-green and presumably anaerobes.
Reason: The first autotrophic organisms were the chemo-autotrophs that never released oxygen.
Reason: The first autotrophic organisms were the chemo-autotrophs that never released oxygen.
Answer : Option D
Explaination / Solution:
Primitive earth was devoid of oxygen so, only those organisms that were able to survive within anaerobic conditions developed. All these were heterotrophic organisms (taking nutrients from outside). Then after autotrophic organisms were developed that used inorganic sources such as H2S,NH3,CH4 as the principle sources of energy. These oganisms are called chemo-autotrophs.
Q6. What is common between vegetative propagation and apomixes
Answer : Option B
Explaination / Solution:
Both vegetative propagation and apomixes are types of asexually reproduction involving not fusion of gametes. So, new progeny produced are identical to parents.
Q7. Examples of local and global nutrient cycles will be:
Answer : Option B
Explaination / Solution:
Phosphorus cycle occurs at local level in an ecosystem as it is mainly derived from soil. Carbon cycles occurs through environment and affected by different ecosystem present on earth surface. So, carbon cycle is global in nature.
Q8. Most industrialized nations are rich financially but poor in
Answer : Option A
Explaination / Solution:
Most industrialized nations are rich financially but poor in biodiversity and traditional knowledge. Biodiversity and traditional knowledge related to bio-resources are can be exploited to develop modern applications.
Q9.
Identify the intra-uterine contraceptive device from the figure given below
Answer : Option A
Explaination / Solution:
Copper-T is an intra-uterine contraceptive device that prevents the implantation of embryo as well as decrease the motility of sperm due to release of copper ions.
Q10. A typical angiospemic embryo sac is though 8 nucleate is 7-celled. 8 nuclei includes
Answer : Option B
Explaination / Solution:
A typical angiospermic embryo sac contains 8 nuclei which includes 3 egg apparatus at micropylar end, 3 antipodal cells at chalazal ends and 2 polar nuclei at the centre of embryo sac.
