Direction : Study the following question carefully and choose the right answer.
Malaria is caused by mosquito bites. Which of the following is the causative microorganism of Malaria?
» Explain it
Many human diseases are caused by microorganisms. Protozoa is the microorganism responsible for Malaria. Some of the other important diseases caused by other microorganisms are –
1)   Bacteria- tuberculosis, cholera, typhoid
2)   Virus- measles, chicken pox, polio, Hepatitis B
Hence, option C is correct.
Which of the following bacteria is involved in fixation of nitrogen In leguminous plants?
» Explain it
Rhizobium lives in the root nodules of leguminous plants such as beans and peas. Rhizobia are special bacteria that can live in the soil or in nodules formed on the roots of legumes. In root nodules, they form a symbiotic association with the legume, obtaining nutrients from the plant and producing nitrogen in a process called biological nitrogen fixation.
Escherichia coli (abbreviated as Ecoli) are bacteria found in the environment, foods, and intestines of people and animals. Ecoli are a large and diverse group of bacteria. Although most strains of Ecoliare harmless, others can make you sick.
Vibrio is a genus of Gram-negative bacteria, possessing a curved-rod shape, several species of which can cause foodborne infection, usually associated with eating undercooked seafood.
Lactobacillus is a genus of Gram-positive bacteria. They are a major part of the lactic acid bacteria group.

Hence, option B is correct.
Yeast is used In the production of 
» Explain it
Yeast is used in the production of alcoholic beverages. Through the process of fermentation, yeast converts sugars into carbon dioxide and alcohol. These two byproducts make yeast an extremely useful tool in food production.

Hence, option B is correct.
The number of nuclei present in a zygote is?
» Explain it
A zygote is the sperm and the egg after they have combined, therefor a zygote has two nuclei.

Hence, option B is correct.
Where is thyroid gland located in our body?
» Explain it
The thyroid gland, or simply the thyroid, is in the endocrine gland in the neck, consisting of two lobes connected by an isthmus. It is found at the front of the neck, below the adam’s apple. The thyroid gland secretes thyroid hormones, which primarily influence the metabolic rate and protein synthesis.
The hormones also have many other effects including those on development.

Hence, option A is correct.