Consider statements about microorganisms: 1. Rhizobium fixes atmospheric nitrogen. 2. Yeast is used in baking. 3. All bacteria are pathogenic. Which are correct? MCQ with Answer and Explanation

Explanation:
The thymus gland is a primary lymphoid organ where T lymphocytes mature and become self-tolerant. Bone marrow is where B cells mature; spleen and lymph nodes are secondary.

Explanation:
Peripatus (velvet worm) is a classic connecting link between the phyla Annelida and Arthropoda. It possesses annelid-like features such as a soft body, segmental arrangement of nephridia, and circular muscles, alongside arthropod-like features such as tracheal respiration, an open circulatory system, and clawed legs. Balanoglossus links Hemichordata and Chordata, and Archaeopteryx links reptiles and birds.

Explanation:
Iron-deficiency anemia is the most prevalent nutritional deficiency worldwide, characterized by fatigue, pallor, and reduced oxygen-carrying capacity. It is treated with iron supplementation and dietary changes.