Which one of the following statements is false in respect of viability of mammalian sperm?
1. | Sperm is viable for only up to 24 hours |
2. | Survival of sperm depends on the pH of the medium and is more active in alkaline medium |
3. | Viability of sperm is determined by its motility |
4. | Sperms must be concentrated in a thick suspension |
Evolution of different species in a given area starting from a point and spreading to other geographical areas is known as:
1. Adaptive radiation
2. Natural selection
3. Migration
4. Divergent evolution
What is the figure given below showing in particular?
1. Ovarian cancer
2. Uterine cancer
3. Tubectomy
4. Vasectomy
In an area where DDT had been used extensively, the population of birds declined significantly because:
1. Birds stopped laying eggs
2. Earthworms in the area got eradicated
3. Cobras were feeding exclusively on birds
4. Many of the birds laid eggs, but the eggs did not hatch
The figure below is the diagrammatic representation of the E.coli vector pBR 322. Which one of the given options correctly identifies its certain components (s)?
1. Ori-original restriction enzyme
2. Rop-reduced osmotic pressure
3. Hind III, Eco RI-selectable markers
4. AmpR, tetiR-antibiotic resistance genes
The common bottle cork is a product of:
1. dermatogen
2. phellogen
3. xylem
4. vascular cambium
Widal test is carried out to test:
1. | Malaria | 2. | Diabetes mellitus |
3. | HIV/AIDS | 4. | typhoid fever |
Which part would be most suitable for raising virus-free plants for micro propagation?
1. Bark
2. Vascular tissue
3. Meristem
4. Node
Which one of the following is a wrong statement?
1. | Most of the forests have been lost in tropical areas |
2. | Ozone in upper part of atmosphere is harmful to animals |
3. | Greenhouse effect is a natural phenomenon |
4. | Eutrophication is a natural phenomenon in freshwater bodies |
Companion cells are closely associated with:
1. Sieve elements
2. Vessel elements
3. Trichomes
4. Guard cells