Need help with all 3 please :)

A. Commensalism because the flatworm benefits while the horseshoe crab doesn't but isn't affected.

B.  Predator-prey since the shark is the predator and the seal is the prey.

C. Competition because the two males are fighting for the female.

Hope this helps :)

thrombocytopenia, which is a deficiency in blood platelets, can cause bleeding and bruising in the dermis similar to senile purpura. other possible causes include: exposure to ultraviolet rays and aging skin are common causes of senile purpura. senile purpura may also be a sign of collagen loss in the skin and bones.

answer : haversian

[explanation: -(compact bone is organized as parallel columns, known as haversian systems, which run lengthwise down the axis of long bones. these columns are composed of lamellae, concentric rings of bone, surrounding a central channel, or haversian canal, that contains the nerves, blood vessels, and lymphatic system of the bone)]