This option is correct because Hektoen Enteric Agar is a selective and differential agar for the isolation and cultivation of the gram-negative enteric microorganisms, especially Salmonella and Shigella. MacConkey Agar is a selective and differential medium designed to isolate and differentiate enterics based on their ability to ferment lactose.

Eosin methylene blue agar and hektoen enteric agar are the correct examples of a Selective and differential media.

Proteus mirabilis and Proteus vulgaris can be differentiated by an indole test. Proteus vulgaris tests positive for the indole test while Proteus mirabilis test negative for the indole test.

All are true statements. The first TEM was built by Max Knoll and Ernst Ruska in 1931. The TEMs are capable of imaging at a significantly higher resolution than the light microscopes, owing to the small de Broglie wavelength of electrons. In TEM, electrons are accelerated by an electric potential and focused by the electrostatic and electromagnetic lenses onto the sample.

This option is correct because among the given tests, only catalase test can be used in the differentiation of Staphylococcus aureus and Streptococcus pyogenes, while the Indole, Voges-Proskauer and Cytochrome C oxidase tests cannot be used to differentiate Staphylococcus aureus and Streptococcus pyogenes.

The methyl red test detects the production of acids formed during metabolism using mixed acid fermentation pathway using pyruvate as a substrate. The pH indicator Methyl Red is added to one tube and a red colour appears at pH's lower than 4.2, indicating a positive test (mixed acid fermentation is used). The solution remaining yellow (pH = 6.2 or above) indicates a negative test, meaning the butanediol fermentation is used.

Blood agar is both a differential and an enriched medium. The blood that is incorporated into this medium is an enrichment ingredient for the cultivation of fastidious organisms such as the Streptococcus species. Chocolate agar is an enriched culture media commonly used for primary isolation of Haemophilus species from clinical specimens.

Voges–Proskauer test is used to detect acetoin in bacterial broth culture. The test is performed by adding alpha-naphthol and potassium hydroxide to the Voges-Proskauer broth which has been inoculated with bacteria. A cherry red colour indicates a positive result, while a yellow-brown color indicates a negative result. Both Enterobacter aerogenes and Klebsiella pneumoniae give positive Voges–Proskauer test.

Alcaligenes faecalis, Enterobacter aerogenes and Klebsiella pneumoniae: All are Gram-negative bacteria.

Plants growing in saline soils are called halophytes. Plants growing on sand and gravel are called psammophytes.

Limnology is the study of freshwater bodies and organisms living therein.

Carboxypeptidase, Collagenase, Carbonic anhydrase and Alcohol dehydrogenase: all are Zn(II) containing enzymes.

Hormones are non-antigenic. They are secreted into blod prior to use and may be amino acids, amino acid derivatives, steroid, polypeptide or proteins, amines or glycoprotein.  

The testes of the male begin to produce testosterone at puberty in response to LH. Progesterone is released by ovary in response to high blood levels of LH.

Asexual reproduction in penicillium takes place by conidia or conidiospores which are developed on conidiospores. When food is plentiful, hydra reproduce asexually by producing buds in the body wall, which grow to be miniature adults and simply break away when they are mature. Gemmules are internal buds found in sponges that are the result of asexual reproduction in response to a hostile environment. In chlamydomonas, asexual reproduction goes through zoospores, palmella stage, alpanospores and hypnospores.