The correct options are option 1 and 3; Platelets. Platelets are also known as thrombocytes and they are found in mammals. They aid in the clotting process which is known in medical terms as homeostasis. They circulate the blood of the mammal and whenever there is an injury and blood is flowing out, they stick to the injured sit and join together to form a clot and stop the flow of blood. Neutrophils are white blood cells and they are not involved in clotting. Fibrinogen is a protein in the blood that is essential to form a clot and is associated with the clotting process.