. The resistance stage in the general adaptation syndrome (stress response) is dominated by

A. Thromboplastin: Thromboplastin (tissue factor) initiates the extrinsic coagulation cascade and promotes clot formation; injecting it would increase clotting, not prevent heart attack or stroke.
B. Fibrinogen: Fibrinogen is the soluble precursor that is converted to fibrin during clot formation; giving fibrinogen would support clot formation, not reduce it.
C. Fibrin: Fibrin is the insoluble protein that forms the mesh of a clot; injecting fibrin would directly contribute to clotting.
D. Factor X: Factor X is a key coagulation factor (when activated to Xa it drives thrombin formation); administering it would promote coagulation rather than prevent it.
E. Heparin: Heparin is an anticoagulant that enhances antithrombin activity and reduces clot formation; it is used to prevent or treat thrombosis and reduce risk of heart attack/stroke.

A. CP: Creatine phosphate (phosphocreatine) is an energy-reserve molecule in muscle that donates phosphate to ADP to regenerate ATP; it is not a second messenger in hormone signal transduction and would not appear as the intracellular signaling oval shown.

B. DPG: 2,3-diphosphoglycerate (2,3-DPG) is an RBC metabolite that modulates hemoglobin’s O₂ affinity; it is not produced as a cytoplasmic second messenger following receptor activation.

C. PEP: Phosphoenolpyruvate (PEP) is a glycolytic intermediate involved in metabolism, not a hormone-activated intracellular signaling molecule.

D. CAMP: Cyclic AMP (cAMP) is a common second messenger produced by adenylate cyclase after many peptide hormones bind cell-surface receptors; the diagram’s small oval (C) inside the cytoplasm leading to downstream effects (D) fits cAMP.