731. No pain is felt while cutting the nails because-
1. Nails are made of the material of dead cells in which there is no blood circulation
2. Nails are a useless part of the body
3. Nails are made of calcium phosphate
4. None of these
Option “1” is correct Nails are usually made up of thick and multiple layers of a type of protein known as ∝ – keratin and are composed of dead tissues. They are devoid of any nerves and blood vessels and therefore we do not feel any pain while the nails are being cut.
732. When does heart rest?
1. Never
2. While sleeping
3. Between two beats
4. While doing yoga
Option “3” is correct Each ‘heartbeat’ consist of a contraction and relaxing of the heart muscles. When the heart contracts, it pumps blood through the blood vessels. When it relaxes, it draws blood in. It takes rest between relaxation and contraction.
733. Lexicography is related to:
1. Structure of human body
2. Compilation of dictionary
3. Secret of handwriting
4. Teaching of pictures and models.
Option “2” is correct Lexicography is related to a glossary of language design, compilation, the evaluation of general dictionaries.
734. On which of the following plant did Gregor Mendal perform his classical experiment?
1. Pea
2. Gram
3. Maize
4. Wheat
Option “1” is correct The genetic experiment Mendal did with pea plant and published his result in 1865.
735. Dinosaurs were in-
1. Paleozoic era
2. Cenozoic era
3. Mesozoic era
4. Pleistocene era
Option “3” is correct Dinosaurs lived between 230 and 65 million year ago, in a time known as Mesozoic Era.
736. The red colour of the red sea is due to the presence of :
1. Moss
2. Bacteria
3. Algae
4. Fungi
Option “3” is correct The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. An alga, of phylum Cyanobacteria called Trichodesmium erythraeum is present in this sea. It contains abundant quantities of pigments, phycobilin, phycoerythrin and phycocyanin, due to which the sea appears red or pinkish.
737. Plants adapted to dry climate are known as-
1. Epiphyte
2. Xerophyte
3. Hydrophytes
4. Mean plants
Option “2” is correct A xerophyte is a species of plant that has adapted to survive in a dry environment.
Option “2” is correct Ichthyology – Study of fish. Entomology – Scientific study of insects. Parasitology – Study of parasitic organisms. Malacology – Study of molluscs.
739. What is hydroponics?
1. Plant without soil enrichment
2. Grafting plant
3. Study of vegetables
4. Soil conservation
Option “1” is correct Hydroponics is a subset of hydroculture and is a method of growing plant using mineral nutrients solutions in water without soil.
740. Dolphins are classified in-
1. Fish
2. Amphibians
3. Reptile
4. Mammals
Option “4” is correct Dolphins are highly intelligent marine mammals and are part of the family of toothed whales. India has declared Ganga Dolphin as the national aquatic animal of India.
