The 'Widal test' is a diagnostic test used to detect the presence of antibodies against the causative agent of: MCQ with Answer and Explanation

Explanation:
Louis Pasteur, through his famous swan-neck flask experiment (1861), demonstrated that life does not arise spontaneously from non-living matter. Sterilized broth in flasks remained sterile unless exposed to airborne microorganisms. Fleming discovered penicillin, Koch established postulates for microbial disease, Jenner developed smallpox vaccine. Pasteur's work was foundational for microbiology.

Explanation:
The limbic system is a complex set of structures in the medial temporal lobe, including the hippocampus, amygdala, and hypothalamus. It is often called the 'emotional brain' and is primarily responsible for processing emotions (fear, anger, pleasure), forming and retrieving memories, and regulating motivation and homeostatic drives (hunger, thirst). The medulla regulates heart rate, the cerebellum coordinates movement, and the occipital/temporal lobes process sensory information.

Explanation:
Adventitious roots arise from stem, leaf, or other non-root tissues, unlike taproots and fibrous roots that develop from the radicle. Examples: prop roots of banyan, stilt roots of maize, aerial roots of orchids. They can serve support, aeration, or additional absorption.