Biology Miscellaneous (Part-IV)

Total Questions: 45

11. A person of mixed European and Indian blood in Latin American is called — [I.A.S. (Pre) 1999]

(a) Mulatto
(b) Mestizo
(c) Meiji
(d) Maumau

Correct Answer: (b) Mestizo

Solution:In Latin America a person of mixed race, especially one having European and American Indian parentage is called mestizo. The term mestizaje, taking as its origin mestizo or ‘mixed’ is the Spanish word for the general process of mixing ancestries.

12. The age of most ancient mountain group is assessed by — [39th B.P.S.C. (Pre) 1994]

(a) Potassium-organ process
(b) C14 process
(c) Ra-Siprocess
(d) Uranium-Lead process

Correct Answer: (d) Uranium-Lead process

Solution:Uranium-lead (U-Pb) process is one of the oldest and most refined methods used to determine the age of ancient mountain rocks that formed from about 1 million years ago or above. Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method of determining the age of an object containing organic material (fossils of dead animals and plants) by using the properties of radiocarbon C-14, a radioactive isotope of carbon.

13. Carbon dating is used to determine the age of — [Uttarakhand P.C.S. (Pre) 2006]

(a) Fossils
(b) Plants
(c) Rocks
(d) None of the above

Correct Answer: (a) Fossils

14. The age of the tree, in years, can be ascertained by: [U.P.P.C.S. (Pre) 2000]

(a) Its weight
(b) Its height
(c) The number of its annular rings
(d) Length of its root

Correct Answer: (c) The number of its annular rings

Solution:The age of the tree, in years, can be ascertained by the number of its annual (or growth) rings in its stem. The number of rings indicates the number of years the tree lived.

15. Consider the statements : [U.P. R.O./A.R.O. (Pre) 2017]

Assertion (A) : Among various types of soils, clay retains highest amount of water.
Reason (R) : Clay has pore spaces of large size.
Select the correct answer using the codes given below :

(a) Both (A) and (R) are true and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.

Correct Answer: (c) (A) is true, but (R) is false.

Solution:Among various types of soils, clay retains highest amount of water because of the presence of small and fine particles. It can have a very high porosity. Because its grains are very small, there are a lot of (small) pore spaces in between them. Hence, assertion (A) is true but Reason (R) is false.

16. Alkaline soils can be improved : [Jharkhand P.C.S. (Pre) 2023]

(a) by the use of lime
(b) by the use of gypsum
(c) by the use of saline water
(d) None of the above

Correct Answer: (b) by the use of gypsum

Solution:Alkaline soils are reclaimed or improved by leaching, crop rotation, providing subsurface drainage area, the addition of gypsum etc. Gypsum application is one of the common amendments used in the reclamation of alkaline soil in India. Quantity of gypsum to be applied depends upon the extent of soil alkalinity, soil texture and crop to be grown.

17. Due to some reasons, if there is a huge fall in the population of species of butterflies, what could be its likely consequence/consequences? [I.A.S. (Pre) 2017]

1. Pollination of some plants could be adversely affected.

2. There could be a drastic increase in the fungal infections of some cultivated plants.

3. It could lead to a fall in the population of some species of wasps, spiders and birds.

Select the correct answer using the code given below :

(a) 1 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

Correct Answer: (c) 1 and 3 only

Solution:Butterflies play a vital role in the pollination of plants and the production of crops by transporting pollen grains from one place to another. Thus, huge fall in the population of species of butterflies could adversely affect the pollination of some plants. Hence, statement 1 is correct.
Butterflies also act as a lower member of the food chain. There are many different creatures that make butterflies part of their diet. Some of the common predators of butterflies include : wasps, ants, parasitic flies, birds, spiders, snakes, toads, rats, lizards, dragonflies, etc. Thus, huge fall in the population of butterflies could lead to a fall in the population of some species of wasps, spiders and birds. Hence, statement 3 is also correct.
Statement 2 is incorrect because the drastic increase in the fungal infections of cultivated plants cannot be correlated with the fall in the population of butterflies.

18. World's most problematic aquatic weed is : [Jharkhand P.C.S. (Pre) 2021]

(a) Eichhornia
(b) Trapa
(c) Wolffia
(d) Azolla

Correct Answer: (a) Eichhornia

Solution:Eichhornia, commonly called water hyacinths, is the world's most problematic aquatic weed. It is also called 'Terror of Bengal'. This plant spreads quickly to create enormous monotypic stands in lakes, rivers, and rice paddies when it comes into contact with the favourable environmental circumstances. Because of its very high rate of growth, it can cover the surface of whole water bodies, choke them and cause a threat to other aquatic life forms.

19. Estuaries possess distinct blooms of excessive growth of a pigmented dinoflagellates. These blooms are : [I.A.S. (Pre) 1998]

(a) Red tides
(b) Sea tides
(c) Black tides
(d) Sea flowers

Correct Answer: (a) Red tides

Solution:An estuary is a partially enclosed body of brackish water along the coast where freshwater from rivers and streams meets and mixes with salt water from the ocean. Due to the presence of dinoflagellates algae, which are abundant in the sediments, form red colour of water. Ultimately this caused by blooms called red tide.

20. Consider the following statements: [I.A.S. (Pre) 2003]

1. The common blue-green algae, Spirogyra and Ulothrix, are found in both freshwater ponds and oceans.

2. The chameleon can look ahead with one eye, and at the same time look behind with another.

Which of these statements is correct?

(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Correct Answer: (b) Only 2

Solution:Spirogyra is a green algae which contains chlorophyll. In the presence of photosynthesis, they make their own food. They are also known as pond silk or blanket weed. They are mostly found in floating surface of freshwater streams and ponds. The chameleon is a species of lizard. It has unique eyes, which can move separately from each other and achieve a visual field of 180 degrees. In this way, it can watch in two different directions at the same time and detect the object on the opposite sides. It has an ability to change the colour of skin.

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