Which one of the following is an example of a negative feedback loop in humans?
| 1. | Constriction of skin blood vessels and contraction of skeletal muscles when it is too cold |
| 2. | Secretion of tears after falling of sand particles into the eye |
| 3. | Salivation of the mouth at the sight of delicious food |
| 4. | secretion of sweat glands and constriction of the skin blood vessels when it is too hot |
Geometric representation of age structure is a characteristic of:
1. Biotic community
2. Population
3. Landscape
4. Ecosystem
Which one of the following mammalian cells is not capable of metabolizing glucose to carbon dioxide aerobically?
1. White blood cells
2. Unsatiated muscle cells
3. Liver cells
4. Red blood cells
Feeling the tremors of an earthquake, a scared resident of the seventh floor of a multi-storey building starts climbing down the stairs rapidly. Which hormone initiated this act?
1. Thyroxine
2. Adrenaline
3. Glucagon
4. Gastrin
Among the human ancestors the brain size was more than 1000 CC in:
1. Homo neaderthalensis
2. Homo erectus
3. Ramapithecus
4. Homo habilis
The length of the DNA molecule greatly exceeds the dimensions of the nucleus in eukaryotic cells. How is this DNA accommodated?
1. Deletion of non-essential genes
2. Super-coiling in nucleosomes
3. DNAse digestion
4. Through the elimination of repetitive DNA
The wavelength of light absorbed by Pr form of phytochrome is:
1. 640 nm
2. 680 nm
3. 720 nm
4. 620 nm
Which part of the ovary in mammals acts as an endocrine gland after ovulation?
| 1. | Graafian follicle |
| 2. | Stroma |
| 3. | Germinal epithelium |
| 4. | Vitelline membrane |
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