The correct answer is ​1, 3 and 4 only.

Key Points

• Convection refers to a process by which heat is transferred by the movement of a heated fluid such as air or water.
• Natural convection results from the tendency of most fluids to expand when heated i.e., to become less dense and to rise as a result of the increased buoyancy.

Examples of Convection:

Rainfall and thunderstorms:

• Clouds are formed when water in the ocean gets warmed and rises up. These warm water droplets, in turn, saturate which leads to the formation of clouds.
• The small clouds which are formed by this process collide with each other to develop bigger clouds. These large clouds which are commonly referred to as cumulonimbus result in rainfall and thunderstorm. Hence, 3 is correct. 

Melting of glaciers:

• The melting of ice is yet another example of convection. The temperature of the surface or boundary of ice increases as warm air blows over the surface; or water, which is at a higher temperature as compared to the ice, flows underneath it.
• As the temperature of the surface or boundary of ice alters, the ice melts. Hence, 4 is correct. 

Land and sea breeze:

• During the day, the land gets heated faster than the water. The air over the land becomes hotter and rises up.
  • The cooler air from the sea rushes in towards the land to take its place. The warm air from the land moves towards the sea to complete the cycle. The air from the sea is called the sea breeze. 
• At night it is exactly the reverse. The water cools down more slowly than the land. So, the cool air from the land moves towards the sea. This is called the land breeze. Hence, 1 is correct.

From the sun the heat comes to us through another process known as radiation.

• It cannot reach us by conduction or convection as there is no medium such as air in most parts of the space between the earth and the sun.
• The transfer of heat by radiation does not require any medium. It can take place whether a medium is present or not. Hence, 2 is not correct.

Explanation:

Latent Heat

• Latent heat is the heat energy required to change the state of matter. 
• if mass m of a substance undergoes a change from one state to the other, then the quantity of heat required is given by
• Q = m L
• Latent heat of fusion is the heat required for solid-liquid change. 
• Latent heat of vaporization is the heat required for liquid-gas change. 
• The latent heat do not change the temperature. 

CONCEPT:

• Wien's displacement law states that- the black-body radiation curve for different temperatures will give the maximum wavelength at a particular temperature and that is inversely proportional to the temperature.

Where λ = wavelength, T = temperature, b = Wien’s constant

Explanation:

Given Data:

Initial wavelength (λ1) = 500 mm, initial temperature (T1) 1227°C = 1500 K and final  temperature (T2) 1000 + 1227°C = 2500 K

• Wien's displacement law can be written mathematically as

The correct answer is Antrum.

• The antrum is not a part of human sperm.

Key Points

Human Sperm:

• It is the male reproductive cell.
• A sperm has three main parts:
  • Head
  • Body
  • Tail
• The head:
  • It contains the nucleus. 
  • The nucleus contains the DNA of the cell.
• The body of the sperm is packed with mitochondria.
• The tail of the sperm helps for its propagation.
• The fine thread of sperm is called the axial filament.
  • It arises from the distal centriole and traverses the body and tail.

Concept:

• The most important and unique characteristic of angiosperms is the participation of both male gametes in the act of fertilization. One male gamete fuses with the egg cell and forms the diploid Zygote. The process is called syngamy or generative fertilization. The  Zygote (2n)  develops into an embryo.
• The other male gamete fuses with two polar nuclei (or secondary nucleus) to form the triploid primary endosperm nucleus. The process is known as a triple fusion or Vegetative fertilization. 
• These two actions of fertilization are together called Double Fertilization.

Explanation:

• The endosperm is the food-laden tissue formed during the development of the angiospermous seed. In angiosperms, the endosperm develops from a triploid (3n) primary endosperm nucleus which is formed as a result of vegetative fertilization, triple fusion or the fusion of a male gamete with the secondary nucleus of the central cell.
• So, the central cell of the female gametophyte act as the endosperm mother cell.

Additional Information

• Synergids: These are 2 elongated cells, present at the micropylar end of the ovule, one on each side of the ovule. The characteristic feature of the synergid cells is the presence of finger-like filiform apparatus. It guides the entry of the pollen tube inside the ovule.
• Antipodal cells: These are three in number present at the chalazal end of the embryo sac. These usually degenerate before/soon after fertilization. Antipodal cells serve to provide nutrition to the pro-embryo.
• Egg: It is a single haploid cell, at the micropylar end, between two synergids.
• It represents the female gamete.
• It, when fertilized by sperm (male gamete), forms a diploid zygote.

The correct answer is Elaioplasts.

Key Points

• The main function of elaioplasts is the synthesis and storage of fatty acids, terpenes, and other lipids, and they can be found in the embryonic leaves of oilseeds, citrus fruits, as well as the anthers of many flowering plants

Additional Information

• Elaioplasts hold the  main function of  synthesis and storage of fatty acids, terpenes, and other lipids, and they can be found in the embryonic leaves of oilseeds, citrus fruits, as well as the anthers of many flowering plants
• Amyloplasts are a type of plastid, double-enveloped organelles in plant cells that are involved in various biological pathways. Amyloplasts are specifically a type of leucoplast, a subcategory for colorless, non-pigment-containing plastids
• Plastids are pivotal subcellular organelles that have evolved to perform specialized functions in plant cells, including photosynthesis and the production and storage of metabolites.

The correct answer is phloem fibres.

Concept:

• A tissue is a group of cells having a common origin and usually performing a common function.
• They form a cellular organizational level, intermediate between the cells and the organ system. 
• Organs are then created by combining the functional groups of tissues.
• The plant body is made up of different kinds of tissues.

The plant tissues can be divided into two main types:

• Meristematic tissue
• Permanent tissue

Permanent tissue can be divided into two types

• Simple permanent tissue- parenchyma, collenchyma, and sclerenchyma
• Complex permanent tissue -xylem and phloem

Explanation:

• Phloem is a food conducting complex permanent tissue.
• Phloem consists of four types of cellular components - sieve tube, companion cells, phloem parenchyma and phloem fibres. 
• Phloem fibres
  • Phloem fibres (bast fibres) are made up of sclerenchymatous cells.
  • These are generally absent in the primary phloem but are found in the secondary phloem.
  • The cell wall of phloem fibres is very thick.
  • These are much elongated, unbranched, and have pointed apices.
  • At maturity, these fibres lose their protoplasm and become dead.
  • They provide mechanical support to the plant.

Additional Information

Companion cells:

• The companion cells are specialized parenchymatous cells, which are closely associated with sieve tube elements. 
• Usually, a single companion cell is found associated with sieve tube elements.
• Companion cells are living cells and do not lose the nucleus at maturity.

​Phloem parenchyma:

• ​Phloem parenchyma is elongated parenchymatous living cells.
• The phloem parenchyma is made up of elongated, tapering cylindrical cells which have dense cytoplasm and nucleus.
• They store food materials and other substances like resins, latex and mucilage.

Sieve tubes:

• Sieve tube elements are specialized cells that are important for the function of the phloem, a highly organized tissue that transports organic compounds produced during photosynthesis.
• Sieve tube elements are living cells and they lose their nucleus and many cell organelles at maturity.

The correct answer is option 2 i.e. Nerve cell.

• In multicellular organisms, cell division is the means of tissue growth and maintenance.
• The growth and division of different cell populations are regulated in different ways, but the basic mechanisms are similar throughout multicellular organisms.
• Most tissues of the body grow by increasing their cell number, but this growth is highly regulated to maintain a balance between different tissues.
• In adults most cell division is involved in tissue renewal rather than growth, many types of cells undergoing continuous replacement.
• Skin cells, for example, are constantly being sloughed off and replaced; in this case, the mature differentiated cells do not divide, but their population is renewed by division of immature stem cells.
• In certain other cells, such as those of the liver, mature cells remain capable of division to allow growth or regeneration after injury.
• In contrast to these patterns, other types of cells either cannot divide or are prevented from dividing by certain molecules produced by nearby cells
• As a result, in the adult organism, some tissues have a greatly reduced capacity to renew damaged or diseased cells.
• Examples of such tissues include heart muscle, nerve cells of the central nervous system, and lens cells in mammals.
• Maintenance and repair of these cells is limited to replacing intracellular components rather than replacing entire cells.

The correct answer is Female Anopheles Mosquito.

Key Points

• Malaria is transmitted by Female Anopheles Mosquitoes.
• Malaria is caused by a Protozoan Parasite called Plasmodium and the carrier is Female Anopheles Mosquito.
• When the mosquito bites the host, the parasite (Plasmodium) is released into the bloodstream.
• It affects Red Blood Cells (RBCs) and the Liver.
• There are four kinds of malarial parasites that infect humans i.e., Plasmodiumvivax, Plasmodium ovale, Plasmodium malariae and Plasmodium falciparum. 
• Malignant malaria is pernicious malaria caused by Plasmodium falciparum.

Additional Information

• Charles Leveran discovered the Malaria Parasite, Plasmodium in the blood of the affected person in 1880.
• Ronald Ross confirmed that Malaria is caused by the malaria parasite and also told that the carrier is mosquito.
• Medicines used to treat malaria are Hydroxychloroquine and Quinine.

Correct answer: 3)

Concept:

• Ionic and covalent are two types of bonds formed between the atoms in a molecule.
• Ionic and covalent bonds depend on the nature of the atoms, i.e., metal element or non-metal element.
• If one is metal and the other is non-metal, then it is an ionic bond, and if both of them are non-metals, then it is a covalent bond.

Explanation:

• Since sodium chloride is formed by the transfer of electrons between the elements, therefore, it is an ionic compound.

Potassium nitrate is a salt with the formula KNO₃. It is an ionic compound consisting of potassium ions K⁺ and nitrate ions 

• Carbon tetrachloride (CCl₄) is a nonpolar covalent compound because the electrons shared by the carbon and chlorine atoms are nearly at the center of the bond.

Calcium sulfate is a compound with the chemical formula of CaSO₄. It is made up of a calcium cation (Ca²⁺) and a sulfate anion 

• When a compound is made up of a metal cation and a polyatomic anion, the compound is considered to be ionic.

Conclusion:

Thus, CCl4 is a covalent compound among the given options.