Haemoglobin is
A. An oxygen carrier in human blood
B. A protein used as food supplement
C. An oxygen scavenger in root nodules
D. A plant protein in which high lysine content

Hint: Hemoglobin is a macromolecule in red blood cells that carries chemical elements to the body's organs and tissues and transports dioxide from organs and tissues back to the lungs.

Step by step answer:Hemoglobin is important for transferring chemical elements in the blood from lungs to the tissues. Myoglobin, in muscle cells, accepts, stores, transports, and releases chemical elements. Hemoglobin may be a molecule within the red blood cells of human blood. it's 2 parts: the haemitin and also the haematohiston. The haemitin contains iron and transports chemical elements from the lungs to the tissues furthermore as it takes dioxide from the tissues to the lungs.
Thus, the correct option is (A).

Note: Normal Hb level varies in adults, howeverHb level in males is 13.8 to 17.2 grams per dl (g/dL) or 138 to 172 grams per metric capacity unit (g/L) and in female is 12.1 to 15.1 g/dL or one21 to 151 g/L.