Which of the following is a trace element? MCQ with Answer and Explanation

Explanation:
Luteinizing hormone (LH) binds to Leydig cells in the testes, stimulating them to produce and secrete testosterone. FSH stimulates Sertoli cells for spermatogenesis. GnRH from hypothalamus stimulates release of LH and FSH.

Explanation:
Pleiotropy is when one gene influences several distinct phenotypic characteristics. Example: sickle cell disease (mutant hemoglobin affects RBC shape, causing anemia, pain, organ damage). Polygenic traits involve many genes, codominance both alleles expressed, epistasis gene interaction.

Explanation:
Diabetes mellitus is characterized by hyperglycemia due to insufficient insulin secretion (Type 1) or insulin resistance (Type 2). Diabetes insipidus is due to deficiency of ADH (vasopressin) affecting water reabsorption. Graves' disease is hyperthyroidism, Addison's is adrenal insufficiency. Insulin deficiency leads to inability of cells to uptake glucose.