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Collectors such as pine oils, fatty acids, xanthates etc. enhance non wettability of ore particles. They stick to the surface of mineral particles and allow them to float.

(i) Zincis refined by electrolytic refining.

(a) This method is based upon the phenomenon of electrolysis.

(b) The crude metal is made anode whereas a thin sheet of pure metal is made cathode.

(c) Electrolyte is the solution of some salt of metal.

(ii) In the extraction of copper, silica (SiO₂) acts as'flux'. It reacts with FeO and removes it as slag (FeSiO₃).

FeO + SiO₂ → FeSiO₃

            (Flux)        slag

(iii) Wrought iron is the purest form of iron.

1. BOD – Biological Oxygen Demand (or) Biochemical Oxygen Demand 

2. BOD refers to the amount of the oxygen that would be consumed, if all the organic matter in one litre of water were oxidized by bacteria.

i. LAB convert milk into curd and are employed in dairy industries.

ii. LAB in human intestine synthesize vitamin B₁₂.

iii. LAB in human stomach, checks the growth of harmful disease causing microbes.

(a) Both A and R are correct and R is the correct explanation of A.

Lactobacillus lactis and Streptococcus lactis bacterias produce acids which cause coagulation of milk protein called casein and changes milk into curd.

(i) Impurities are more soluble in molten state than in solid state of the metal.

(ii) Different components of a mixture are differently adsorbed on an adsorbent.

1. Yes, BOD test measures the rate of uptake of oxygen by micro organisms in a sample of water, indirectly. BOD is the measure of the organic matter present in water.

2. biochemical oxygen demand.

By measuring BOD of a water body, health workers find the amount of dissolved oxygen in water. The lesser the amount of dissolved oxygen, the more polluted the water body will be.

Auto immune response

Eg: Rhuematoid arthritis, Myasthenia gravis.

i. LAB—Lactic Acid Bacteria.

ii. BOD—Biochemical Oxygen Demand.

The fruit juices bought from market are clearer because they have been clarified by pectinases and proteases.

The fruit juices prepared at home are turbid due to the presence in it of fibers and pectin whereas those purchased from the market are clearer because of the use of enzymes like proteases and pectinases which remove turbidity.

(a) The bottled fruit juices bought from the market are clearer as compared to those made at home which are turbid due to the presence of fibers, pectin, etc. This is because the bottled juices are made clear by the use of the enzymes pectinases and proteases. 

(b) Cyclosporin : A is a bioactive molecule produced by Trichoderma polysporum, which is used as an immuno-suppressive agent in organ transplant patient. It prevents rejection reactions in organ transpiantation. Statins are produced by the yeast Monascus purpureus and have been commercialized as cholesterol-lowering agent.

No, dragon flies eat mosquito larva and act as bio control agents.

Bottle juices are clarified by the use of pectinase and proteases.

(a) Sample 4

(b) Floes- masses of bacteria associated with fungal laments to form mesh like structures. They consume the major part of the organic matter in the effluent. This is significantly reduces the BOD of the effluent.

BOD stands for biochemical oxygen demand which represents the amount of dissolved oxygen that would be consumed if all the organic matter in one litre of water were oxidised by microorganisms. More BOD value means the water sample is polluted by organic matter.

Sample 'C‘ is most polluted because it has highest BOD level among the three samples of water.

Synthetic resins are artificially synthesised high molecular weight polymers. They are the basic raw material of plastic. The main properties of plastic depend on the synthetic resin it is made from.

Examples of natural resins : Rosin, Damar, Copal, Sandarac, Amber, Manila 

Examples of synthetic resins : Polyester resin, Phenolic resin, Alkyl resin, Polycarbonate resin, Polyamide resin, Polyurethane resin, silicone resin, Epoxy resin, Acrylic resin.

Correct answer is

(c) chemical compounds

Correct option: (D) Lichens grow in cities.

Polymer that contains amide linkage : Nylon-6; Nylon 6, 6.

Compare the stability of anion formed after the loss of H⁺ ion. More stable the anion formed, more easy will be the dissociation of O—H bond, stronger will be the acids.

• Lichens are sensitive to air pollutants especially to sulphur-di-oxide. 
• Therefore,considered as pollution indicators. 

Yes, a person can do a complete detailed study of each of those animals. Classification of animals based on characteristics into various groups has made it easier to study them.

Correct option: (A) air pollution

Phylum Arthropoda is most diverse and populous.

1. Cockroach rearing industry is a booming industry in China. Cockroaches are reared in more than hundred farms in China. A giant farm in China produces around 6 billion cockroaches. 

2. It is believed that cockroaches can be used to prepare a medicine that can prevent stomach cancer. They are also used to treat compost waste.

1. Cockroaches have compound eyes whereas humans have simple eyes. 

2. Eyes of cockroach possess several ommatidia that collectively form an image and help them to detect even the slightest movement of its predator. They provide mosaic or hazy vision. 

3. Human eyes contain single lens and a clear image is formed on the retina. Humans have binocular vision which provides an improved perception of depth and gives a three dimensional image of their surroundings.

The body cavity of cockroach is known as haemocoel as it is filled with haemolymph (blood). Cockroaches have open type of circulation thus; the body cavity is filled with haemolymph.

The functional difference between the respiratory systems of cockroach and human being is that in respiratory system of cockroach transport of gases does not occur via. blood whereas in human respiratory system transport of gases takes place via blood. In cockroach, the circulatory system has no role in respiratory process whereas in humans, circulatory system plays an important in respiratory process.

1. The gizzard in cockroach is a spherical organ which has chitinous teeth and bristles. 

2. The chitinous teeth present in gizzard are responsible for crushing the food and the bristles help to filter the food. 

3. If the cockroach did not have gizzard, the food will not be crushed into small particles and unfiltered food will enter the hindgut. Thus, digestion will be affected in the absence of gizzard.

Systematic position of cockroach:

13 chambers are present in heart of a cockroach, out of which 10 chambers are in abdominal region and 3 are in thoracic region.

The substances which reduce the rate of transpiration in plants without affecting CO₂ fixation in photosynthesis or plant growth are called antitranspirants. 

Loosely arranged parenchyma like cells present just beneath the air chamber of hydathode are called Epithem.

As the wind blows the rate of transpiration increases because wind removes the saturated water vapours accumulated around the stomata during blowing and increases the rate of transpiration.

(i) The lower surface of a dorsoventral dicotyledonous leaf possesses greater number of stomata. In an isobilateral / monocot leaf, the number of stomata are equal on both of its surfaces. 

(ii) The transpiration from a leaf depends on thickness of stationary layer of air/boundary layer that is in immediate contact with leaf. 

(iii) It depends on surface features of the leaf such as hardness of the leaf surface as well as wind speed. 

(iv) The thinner the boundary layer, the greater is transpiration. 

(v) There must be diffusion gradient between boundary layer and atmosphere on one side and stomatal cavity on the other side for transpiration.

The rate of transpiration increases with an increase in root-shoot ratio because of greater availability of water due to more extensive root system.

(a) Asymmetric Digital Subscriber Line

A company has to invest in research and development, hire very high level industry experts, pay high salaries to them as well as other highly qualified managers, etc. and so…

True 

All of the above are audio file extensions.

The company needs to observe strict legal provisions and other provisions laid by SEBI lifetime. It has to submit its statements, reports, accounts, etc. to the registrar on a regular basis.

976 Hymns of Guru Nanak Dev Ji have been included in Adi Granth sahib.

The representatives of Guru Arjan Dev Ji were called the Masands.

Adi Granth Sahib was placed in Sri Harmandir Sahib at Amritsar.

(c) WAVE is an audio format, rest are image file extensions.

Guru Arjari Dev Ji.