Select the correct statement from the following:

1.	Biogas is produced by the activity of aerobic bacteria on animal waste
2.	Methanobacterium is an aerobic bacterium found in the rumen of cattle
3.	Biogas, commonly called gobar gas, is pure methane
4.	Activated sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria

Select the two correct statements out of the four (a-d) given below about lac operon:

The correct statements are:

Keel is characteristic of the flowers of:
1. Gulmohur
2. Cassia
3. Calotropis
4. Bean

The kind of epithelium which forms the inner walls of blood vessels is:
1. cuboidal epithelium
2. columnar epithelium
3. ciliated columnar epithelium
4. squamous epithelium

Which one of the following has its own DNA?
1. Mitochondria
2. Dictyosome
3. Lysosome
4. Peroxisome

Transfer of pollen grains from the anther to the stigma of another flower of the same plant is called:

1. xenogamy

2. geitonogamy

3. karyogamy

4. autogamy

The genotype of a plant showing the dominant phenotype can be determined by:

1. test cross

2. dihybrid cross

3. pedigree analysis

4. back cross

PGA as the first CO₂ fixation product was discovered in photosynthesis of:
1. Bryophyte
2. Gymnosperm
3. Angiosperm
4. Algae

Study the four statements (a–d) given below and select the two correct ones out of them:

The two correct statements are:
1. a and d
2. a and b
3. b and c
4. c and d

Seminal plasma in human males is rich in:

1. fructose and calcium

2. glucose and calcium

3. DNA and testosterone

4. ribose and potassium