Choose the best answer:

a) Algal bloom leads to loss of species diversity which is known as _______. (Eutrophication, Pasteurisation)

b) Which one of the following cause amoebic dysentery? (Entamoeba histolytica, Plasmodium vivax, Plasmodium falciparum)

c) Milk is heated to 72^o C for 30 minutes and then suddenly cooled to12^o C. Microbes are killed without causing damage to the taste and quality of milk. Name this process (dehydration, pasteurisation)

d) Nodules are responsible for nitrogen fixation. Name the bacteria present inside the root nodules. (Acetobactor, Rhizobium, Clostridium)

a) Eutrophication

In some conditions, the algae produce thick material masses, called 'bloom' which covers the upper surface of a water body (usually standing water like pond, lake) like a carpet. This cuts off the oxygen supply to water under the bloom and thus decreasing oxygen content, leading to the death of aquatic species. This is called Eutrophication.

b) Entamoeba histolytica

Entamoeba histolytica is a protozoan, which contaminated food and water easily, if proper hygienic conditions are not maintained. Thus, the microorganisms can enter our alimentary canal and damage it, causing amoebic dysentery. In this, one experiences pain in abdomen and blood in stools.

c) Pasteurisation

Louis Pasteur developed the method of preservation of food (mainly milk) by process of heating at specified temperature for a given duration of time. The technique was thus named Pasteurisation.

d) Rhizobium

Nitrogen plays an important role in life processes, specially for plants. As plants cannot take in nitrogen directly, they are helped by some bacteria for this purpose. Rhizobium are present inside the root nodules and help in fixing the atmospheric nitrogen for the plant.