The specific region where the exchange of gases occurs between air and blood in the lungs is the: MCQ with Answer and Explanation

Explanation:
Iodine atoms are incorporated into thyroxine (T₄, 4 iodine atoms) and triiodothyronine (T₃, 3 iodine atoms) synthesized by thyroid follicular cells. Iodine deficiency leads to goiter and hypothyroidism. Iron is in hemoglobin, calcium in bones, phosphorus in ATP and bones.

Explanation:
COVID-19 is caused by SARS-CoV-2, a novel coronavirus. Tuberculosis is bacterial (Mycobacterium). Influenza is caused by influenza viruses (Orthomyxoviridae), not coronavirus. Pneumonia can be bacterial or viral, but the question specifies Streptococcus which is bacterial. COVID-19 emerged in 2019, causing a global pandemic, primarily affecting the respiratory system.

Explanation:
Blood group O lacks A and B antigens on red cells but contains both anti-A and anti-B antibodies in plasma. This makes it the universal donor for packed red cells but dangerous plasma donor. Group AB has no antibodies. So, the presence of both antibodies is correct.