For the benefit of NDA & NA (II) Exam 2017 aspirants, Jagran Josh is providing practice questions on biology. The answers to the questions along with detailed explanations will help the aspirants in improving their scores in the General Science section of GAT paper. The questions are given below.
1. The most effective wavelength of visible light in photosynthesis is in the region
d) Both b and c
Ans. (d) Both b and c
Green light is reflected by the leaves, thus making it the least effective. The most effective lights are blue and red light as there are two activity peaks at these wavelengths. Otherwise, this activity occurs at many different wavelengths, with the only difference that its efficiency differs from wavelength to wavelength.
2. Pashmina is a breed of
Ans. (a) Sheep
Pashmina shawls are made of the fibre derived from these sheep.
3. The thermoregulatory organ of the body is
a) Pituitary gland
Ans. (b) Hypothalamus
The hypothalamus serves as a natural thermostat of the body and regulates its temperature. We perspire or shiver, depending on whether our body would like to gain or lose heat. It is a crucial part of the internal stable environment maintained by hypothalamus to permit optimum bodily functions- called homeostasis. The pituitary is called the Master Gland.
4. Whose milk contains the most fat?
Ans. (b) Camel
Reindeer is domesticated by the Eskimos in very cold, icy environments. The percentage of fat in a particular variety of mil determines its thickness. Fats, milk solids and other nutrients are present in milk to varying extents.
5. The malarial fever starts
a) Just after the mosquito bite
b) After the parasites reach the liver
c) After the bursting of RBCs
d) After the toxin is released by blood
Ans. (d) After the toxin is released by blood
Malaria is accused by Plasmodium, a protozoan. It is carried by the female Anopheles mosquito in unhygienic conditions. The parasites multiply after entering the body and it is when the toxins reach the blood that the fever begins.
6. Shifting cultivators normally grow
a) A single crop which is mainly consumed
b) The major crop along with cereals
c) Cash crop along with fodder
d) Grains, vegetables and tubers in rotation
Ans. (a) A single crop which is mainly consumed
Shifting cultivation, called jhumming in north-east India, involves cultivating a field for some time and then burning the residue to move to another place for cultivation. It is an utterly wasteful exercise, which pollutes the environment, too.
7. What is mixed farming?
a) The growing of two crops simultaneously
b) The combination of farming and industry
c) Farming coupled with animal husbandry
d) Collective farming
Ans. (c) Farming coupled with animal husbandry
The two activities of agriculture and animal husbandry was are integrated to ensure that there is no wastage of time or materials, For instance, the farm waste can be a part of the animal feed while their refuse can be suitably used as manure or to produce biogas, a clean form of energy.
8. The three communicable diseases prevalent in developing countries caused by unsafe drinking water and bad sanitation are
a) acute diarrhoea, cancer and gout
b) malaria, acute diarrhoea and plague
c) onchocerciasis, leukemia and arthritis
d) rheumatism, malaria and AIDS
Ans. (b) malaria, acute diarrhoea and plague
Other options contain at least non-communicable disease. Malaria is spared by mosquitoes as they carry Plasmodium, the causal microbe. Diarrhea is caused by bacteria.
9. Xerophthalmia is caused due to the deficiency of
c) Vitamin A
Ans. (c) Vitamin A
Vitamin A has a significant role in preventing night blindness, in which the patient is unable to see in conditions of dim light or darkness. Xerophthalmia causes dry eyes, due to a problem with the eye glands. A deficiency of Calcium can cause bone problems.
10. Which of the following has been described as the most powerful food on the earth?
a) blue-green algae
Ans. (b) sunova
Called Sunova spirulina. It contains immense amounts of protein and that’s why it has been named so by the WHO. One gram of sunova contains proteins equal to those found in one tone of vegetables. It is used during space flights by astronauts.