Identify the correct statement about the human excretory system: MCQ with Answer and Explanation

Explanation:
Candidiasis (thrush) is an opportunistic fungal infection caused by Candida albicans, affecting moist areas like mouth, vagina, and skin folds. Ringworm is caused by dermatophytes, athlete's foot by Trichophyton, aspergillosis by Aspergillus.

Explanation:
Leptin is a peptide hormone produced primarily by adipocytes (fat cells). Its concentration in the blood is proportional to the amount of body fat. Leptin acts as a satiety signal, crossing the blood-brain barrier to act on receptors in the hypothalamus. It suppresses appetite (anorexigenic effect) and increases energy expenditure, thereby regulating long-term food intake and body weight. It is often called the 'satiety hormone' or 'fat hormone'.

Explanation:
Glucagon is a peptide hormone secreted by the alpha cells of the pancreatic islets in response to low blood glucose levels (hypoglycemia). Its primary target is the liver, where it acts to raise blood glucose levels. It stimulates glycogenolysis (the breakdown of stored glycogen into glucose) and gluconeogenesis (the synthesis of new glucose from non-carbohydrate sources like amino acids and glycerol). It also promotes the breakdown of fats (lipolysis) in adipose tissue. It has the opposite effect of insulin.