Question

lo 2.1. what are platelets responsible for?
blood clotting.
breaking down old blood cells.
oxygen transport.
filtering waste from the blood.
transporting oxygen in the blood.

Explanation:

Platelets, also known as thrombocytes, are cell - fragments in the blood. Their main function is to form blood clots (hemostasis) when there is a blood vessel injury. Red blood cells are responsible for oxygen transport (both "Oxygen transport" and "Transporting oxygen in the blood" are related to red blood cells). The spleen and liver are involved in breaking down old blood cells. The kidneys are mainly responsible for filtering waste from the blood.

Answer:

Blood clotting.