1) The correct option is B (assertion and reason is correct but reason is not correct explanation of assertion) 

• Turbidity refers to the light scattering properties of a sample. Turbidity can be described as “haziness” or “milkyness,” and is caused by fine particles scattering light at more or less 90 degrees to the direction from which the light enters the sample. Turbidity is not to be confused with color, nor color with turbidity.
• Turbidity is normally measured using an electronic device in which a beam of ordinary white light is directed through a certain path length of the sample.
• Turbidity is the capacity of water to disperse and absorb light, preventing its transmission in depth. It depends on suspended and dissolved solids including pelagic organisms (plankton). Turbidity is a parameter measured in situ, and is directly related to the visual appearance of water.
• This is due to the fact that the food coloring is less dense than the milk, so it floats on the surface. The colors do not mix because they were not stirred. When the soap is added, the soap reduces the surface tension of the milk by dissolving the fat molecules

2)  The correct option is A (assertion and reason is correct and reason is correct explanation of assertion) 

• Sols are big enough to scatter a beam of light passing through them and make its path visible. The particles of a suspension scatter a beam of light passing through it and make its path visible. The solute particles do not settle down when left undisturbed, i.e., a solution is stable.
• Light appears to travels in straight line because its wavelength is very small .The light hits the screen in a region where straight lines can be drawn from the light source just clipping the hole in the barrier and then continuing them on to the screen.

3) The correct option is A (assertion and reason is correct and reason is correct explanation of assertion)

• Cellulose is an unbranched polymer of glucose residues put together via beta-1,4 linkages, which allow the molecule to form long and straight chains. This straight chain conformation is ideal for the formation of strong fibers.
• The glucose units in cellulose are linked by β glycosidic bonds, different than the α glycosidic bonds found in glycogen and starch. Cellulose has more hydrogen bonds between adjacent glucose units, both within a chain and between adjacent chains, making it a tougher fiber than glycogen or starch.
• Fibre assists your digestive system – keeping food moving through the gut and pushing waste out of the body. Animals, such as cows, sheep and horses, can digest cellulose, which is why they can get the energy and nutrients they need from grass.
• Cellulose is a polysaccharide (a form of carbohydrate) that has a structural role in animals and plants.Most animals can't digest cellulose because it is so hard to break down. Animals that eat only plants (herbivores) have special sacs in their digestive system to help break down cellulose.