Which of the following vitamins is also known as 'retinol'? MCQ with Answer and Explanation

Explanation:
Human Immunodeficiency Virus (HIV), the causative agent of Acquired Immunodeficiency Syndrome (AIDS), is a retrovirus that specifically targets and destroys CD4+ T helper cells, which are crucial for coordinating the adaptive immune response. As the CD4+ count drops, the immune system becomes severely compromised, leading to opportunistic infections and certain cancers. Hepatitis B targets the liver, Herpes causes lesions, and Influenza targets the respiratory tract.

Explanation:
During metaphase, chromosomes are maximally condensed and align at the cell equator (metaphase plate) attached to spindle fibers via kinetochores. This alignment ensures equal segregation. In prophase, chromosomes condense; anaphase, sister chromatids separate; telophase, nuclear envelope reforms. Metaphase is the best stage for studying chromosome morphology for karyotyping.

Explanation:
Pernicious anemia is a megaloblastic anemia resulting from vitamin B₁₂ (cobalamin) deficiency, often due to lack of intrinsic factor (produced by stomach parietal cells) needed for its absorption. It is characterized by large, immature red blood cells and neurological symptoms. Iron deficiency causes microcytic anemia. Sickle cell is genetic, aplastic is bone marrow failure.