Hemoglobin is a protein that binds to oxygen. it is only produced by red blood cells and it allows blood to transport oxygen throughout the body.

The statements are true.

Hemoglobin (Hb), is the oxygen-transport metalloprotein which contains iron in the centre of its structure. This metalloprotein is found in the red blood cells (erythrocytes). The function of hemoglobin is to transport the oxygen through the blood carries from the lungs to the rest of the tissues. Oxygen is necessary for the aerobic respiration in order to provide energy for the functions of the organism (metabolism).

i am going to guess that it is co2.

nucleic acid molecules are incredibly complex, containing the code that guarantees the four different nucleotide units comprise dna, the nucleic acid of interest to the genealogist. and one of four nitrogen-containing molecules called nucleotides