A major component of gobar gas is:

1.	Methane	2.	Ethane
3.	Butane	4.	Ammonia

A free-living nitrogen-fixing cyanobacterium that can also form a symbiotic association with the water fern Azolla is:

1. Chlorella

2. Nostoc

3. Anabaena

4. Tolypothrix

In the ABO system of blood groups, if both antigens are present but no antibody, the blood group of the individual would be:

Plants adapted to low light intensity have:

The Ti plasmid is often used for making transgenic plants. This plasmid is found in:

1. Rhizobium of the roots of leguminous plants

2. Agrobacterium

3. Yeast as a 2 µm plasmid

4. Azotobacter

During the replication of bacterial chromosomes, DNA synthesis starts from a replication origin site and:

1. Is facilitated by telomerase

2. Moves in one direction of the size

3. Moves in a bi-directional way

4. RNA primers are involved

In a plant, red fruit (R) is dominant over yellow fruit (r) and tallness (T) is dominant over shortness (t). If a plant with RRTt genotype is crossed with a plant that is rrtt:

1. 50% will be tall with red fruit

2. 75% will be tall with red fruit

3. All the offspring will be tall with red fruit

4. 25% will be tall with red fruit

After a mutation at a genetic locus, the character of an organism changes due to the change in:

1. DNA replication

2. Protein synthesis pattern

3. RNA transcription pattern

4. Protein structure 

According to Oparin, which one of the following was not present in the primitive atmosphere of the earth?

When CO₂ concentration in blood increases, breathing becomes: