Science (English Medium) कक्षा १२ - CBSE Question Bank Solutions for Biology

Which type of cell division forms spermatids from the secondary spermatocytes?

How many spermatozoa are formed from one secondary spermatocyte?

In a monohybrid cross of plants with red and white flowered plants, Mendel got only red-flowered plants. On self-pollinating these F1 plants got both red and white flowered plants in 3:1 ratio. Explain the basis of using RR and rr symbols to represent the genotype of plants of parental generation.

In a plant tallness is dominant over dwarfness and red flower is dominant over white. Starting with the parents work out a dihybrid cross. What is standard dihybrid ratio? Do you think the values would deviate if the two genes in question are interacting with each other?

Wastewater treatment generates a large quantity of sludge, which can be treated by ______.

The primary treatment of waste water involves the removal of ______.

BOD of waste water is estimated by measuring the amount of ______.

What would happen if oxygen availability to activated sludge flocs is reduced?

Activated sludge should have the ability to settle quickly so that it can ______.

Why do we prefer to call secondary waste water treatment as biological treatment?

Name the states involved in Ganga action plan.

What is the group of bacteria found in both the rumen of cattle and shidge of sewage treatment?

Why are flocs important in biological treatment of waste water?

Why is aerobic degradation more important than anaerobic degradation for the treatment of large volumes of waste waters rich in organic matter. Discuss.

Discuss about the major programs that the Ministry of Environment and Forests, Government of India, has initiated for saving major Indian rivers from pollution.

Ganga has recently been declared the national river. Discuss the implication with respect to pollution of this river.

What would happen if a large volume of untreated sewage is discharged into a river?

In what way anaerobic sludge digestion is important in sewage treatments?

What does ‘competent’ refer to in competent cells used in transformation experiments?

What modification is done on the Ti plasmid of Agrobacterium tumefaciens to convert it into a cloning vector?