Name the blood cells in which nucleus is absent
Answer: B
Blood platelets have no nucleus.
They are not whole cells but fragments budded off from the giant megakaryocytes of the bone marrow, so they carry no nucleus and live only about ten days. Mature red cells likewise lose theirs; all the white cells keep them.
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Branch of science which deal with the study of causative agent of disease is __________
Answer: B
The study of the causes of disease is etiology, from the Greek aitia, cause.
It identifies the agent, whether infective, genetic, nutritional or environmental. Pathology, by contrast, studies the changes the disease produces in the tissues.
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Which component of plants receives stimulus for flowering?
Answer: C
The leaves receive the stimulus for flowering.
They contain the phytochrome that measures the length of the dark period, and produce the flowering signal - florigen, now identified as the FT protein - which travels through the phloem to the shoot tip, where the flower is actually formed.
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Plants synthesise protein from
Answer: D
Plants build protein from amino acids.
They make the amino acids themselves, combining the carbon skeletons from photosynthesis with nitrogen taken up as nitrate. Animals cannot do this for the essential amino acids and must obtain them from food.
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Water is conducted in vascular plant by-
Answer: D
Water is conducted in a vascular plant by the xylem.
Its tracheids and vessels are dead, hollow, lignified cells forming continuous tubes from root to leaf. Water is drawn up them by the pull of transpiration, helped by the cohesion between water molecules. Phloem carries food, in both directions.
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Who is known as father of medicine
Answer: C
Hippocrates is called the father of medicine.
Working on Kos in the fifth century BC, he separated medicine from superstition, insisting that disease has natural causes. The Hippocratic Oath is named after him.
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Smallest bone of human body is _________
Answer: D
The stapes is the smallest bone in the body, about 3 mm long.
It is the innermost of the three ear ossicles - malleus, incus and stapes - which transmit the vibration of the eardrum to the oval window of the cochlea, amplifying it about twentyfold.
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Tissue in which cells have lost the capacity of cell division
Answer: B
Cells that have lost the capacity to divide form permanent tissue.
They arise from meristematic cells that have differentiated and taken on a fixed shape and function - parenchyma, collenchyma, sclerenchyma, xylem and phloem. Only meristems retain the power of division.
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Plants receive their nutrients mainly from ?
Answer: D
Plants take their nutrients mainly from the soil - nitrogen, phosphorus, potassium and the micronutrients, absorbed in solution through the root hairs.
Light supplies energy and chlorophyll captures it, but neither is a nutrient; the carbon comes from the air as carbon dioxide.
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Crop sown at the commencement of the monsoon is called
Answer: C
A crop sown at the onset of the monsoon is a kharif crop.
Kharif crops are sown in June and July and harvested in September and October - rice, maize, jowar, bajra, cotton and jute. Rabi crops are sown in October and November and harvested in spring.
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