Answer: B) chitin Explanation: Many carbohydrates contain one or more modified monosaccharide units that have had one or more groups replaced or removed.   Chitin is one of many naturally occurring polymers. It is one of the most abundant natural materials in the world. Over time it is bio-degradable in the natural environment. Its breakdown may be catalyzed by enzymes called chitinases, secreted by microorganisms such as bacteria and fungi, and produced by some plants.   Chitin is composed of repeating units of N-acetylglucosamine, a nitrogen-containing form of glucose.

Answer: B) FALSE Explanation: FALSE. Each hemoglobin molecule can transport four molecules of oxygen.   Hemoglobin, or Hb, is a protein molecule found in red blood cells (erythrocytes) made of four subunits: two alpha subunits and two beta subunits. Heme the component of hemoglobin responsible for binding oxygen consists of an iron ion that binds oxygen and a porphyrin ring that binds the globin molecules, one molecule binds one molecule of oxygen and can bind up to four oxygen molecules.

Yesterday, is what we will never see again as the time we come across will never be back.

Answer: C) India Explanation:

Answer: B) 4 Explanation: