The type of joint that allows movement in one plane, like the elbow and knee, is: MCQ with Answer and Explanation

Explanation:
Kala-azar, also known as visceral leishmaniasis, is caused by the protozoan parasite Leishmania donovani. It is transmitted by the bite of the infected female sandfly (Phlebotomus). The disease affects internal organs, particularly the liver, spleen, and bone marrow, causing prolonged fever, weight loss, and enlargement of the liver and spleen. Trypanosoma brucei causes sleeping sickness, and Plasmodium causes malaria.

Explanation:
Biological Oxygen Demand (BOD) is a measure of the amount of dissolved oxygen required by aerobic microorganisms (mainly bacteria) to decompose the organic matter present in a given volume of water sample at a specific temperature over a specific time (usually 5 days at 20°C). High BOD indicates high levels of organic pollution, which depletes oxygen for aquatic life.

Explanation:
pUC19 is a small, high-copy-number cloning vector. A crucial feature for selecting recombinant clones is the presence of the lacZ' gene, which codes for the alpha-peptide of beta-galactosidase. The multiple cloning site (MCS) is located within this lacZ' gene. When foreign DNA is inserted into the MCS, it disrupts the lacZ' gene (insertional inactivation). On media containing X-gal and IPTG, colonies with empty vectors turn blue, while colonies with recombinant plasmids (disrupted lacZ') remain white, allowing easy visual selection.