Final answer:
The statement is true; venous blood in systemic circulation has less oxygen and more carbon dioxide because it has delivered oxygen to tissues and picked up carbon dioxide.
Step-by-step explanation:
The statement that venous blood in systemic circulation is poorer in oxygen and richer in carbon dioxide is true. In the systemic circulation, oxygen-rich blood leaves the heart through the aorta and distributes oxygen to the body's organs and tissues via the arteries. After releasing oxygen and absorbing carbon dioxide from the tissues, the blood becomes oxygen-poor and is then collected back into veins, such as the inferior vena cava and superior vena cava, to complete the systemic circulation. This deoxygenated blood is taken back to the heart and then to the lungs where it releases carbon dioxide and absorbs fresh oxygen during pulmonary circulation.
Thus, as blood moves from the systemic capillaries to the veins within body tissues, partial pressure of oxygen (Po₂) drops, and partial pressure of carbon dioxide (Pco₂) increases due to the exchange of gases in the tissues, following their respective pressure gradients.