Answers could include two of the following.

Lungs:

→ As blood passes through the lungs, deoxygenated blood becomes oxygenated.

→ Carbon dioxide is also removed from the blood and exhaled.
 

Kidneys:

→ In the kidneys, blood is filtered to remove waste products like urea, excess salts, and water, which are excreted as urine.

→ The blood leaving the kidneys has a reduced concentration of these waste products, and its composition is more balanced in terms of water and electrolyte levels.
 

Liver:

→ The liver modifies the blood by metabolising nutrients, detoxifying harmful substances, and storing or releasing glucose as needed.

→ Blood exiting the liver has a regulated concentration of glucose and may have reduced levels of toxins, as the liver converts harmful compounds into safer by-products for excretion.

→ The pulmonary circuit is the part of the circulatory system that carries deoxygenated blood from the heart to the lungs for oxygenation and then returns oxygenated blood back to the heart

→ Deoxygenated blood entering the lungs has low oxygen levels and high carbon dioxide levels. As it passes through the alveolar capillaries, oxygen diffuses into the blood while carbon dioxide diffuses out.

→ This process results in blood leaving the lungs with higher oxygen content and lower carbon dioxide levels.

→ Additionally, the blood slightly cools as it passes through the lungs due to its proximity to the air in the alveoli and the evaporation of water vapour during exhalation.

→ The pH of the blood also slightly increases as carbon dioxide (which forms carbonic acid in blood) is removed.