Which component of the blood is essential in transporting oxygen to body cells?

A. While this option lists some food items, it is incomplete and includes “citrus” separately, which is already part of the fruit group, and “cheese” separately instead of as part of the broader dairy category.

B. The USDA food patterns include five main food groups: grains, vegetables, fruits, dairy, and protein foods. These patterns are designed to provide balanced nutrition, ensure adequate intake of essential nutrients, and promote overall health. Protein foods include lean meats, poultry, seafood, eggs, nuts, seeds, and legumes. The patterns emphasize whole grains, a variety of colorful vegetables and fruits, low-fat or fat-free dairy products, and lean protein sources. These food groups form the foundation of healthy eating recommendations, such as those presented in MyPlate.

C. This option is incomplete because it omits vegetables and dairy, which are essential food groups in the USDA guidelines.

D. While fruits, vegetables, and whole grains are important, this option leaves out dairy and protein foods, making it incomplete according to USDA recommendations.

A. Hemoglobin is an iron-containing protein found in red blood cells. Its main role is to bind oxygen in the lungs and deliver it to tissues while carrying carbon dioxide back to the lungs for exhalation. Hemoglobin is a component of erythrocytes, not the fluid portion of blood.

B. Plasma is the straw-colored fluid portion of blood and constitutes approximately 55% of total blood volume. Plasma is about 90% water and contains essential substances such as: proteins (albumin, globulins, fibrinogen), electrolytes (sodium, potassium, calcium), nutrients (glucose, amino acids, fatty acids), hormones, and metabolic waste products (urea, carbon dioxide). Plasma serves multiple vital functions: it acts as a transport medium for blood cells, nutrients, hormones, and waste products; helps maintain blood pressure and volume; plays a key role in coagulation and immunity; and supports the body’s acid-base balance.

C. Lymph is a fluid that circulates within the lymphatic system. It carries immune cells, removes excess interstitial fluid from tissues, and returns it to the bloodstream. While plasma and lymph are similar in composition, lymph is not part of the circulatory blood system and does not constitute the fluid portion of blood.

D. Platelets, or thrombocytes, are small cell fragments responsible for blood clotting. They circulate suspended in plasma but are not the fluid portion themselves. They participate in hemostasis and wound repair.