If, in response to a complaint, Lin denies that she is responsible for Martino's harms, and further, that Martino actually caused harm to her, what is this called?

counterclaim

Explanation:

counterclaim is defensive process in which person or party  made opposing claim. If one party file case against other it is called claim and if other party file case against first party to offset claim it is known as counterclaim. i-e if company A file claim that company B fraud in contract it is known as claim and similarly if company B files claim that Company A is responsible and made fraud it is known as counterclaim in legal action.

the united states constitution is the supreme law of the united states. the constitution, originally comprising seven articles, delineates the national frame of government. its first three articles embody the doctrine of the separation of powers, whereby the federal government is divided into three branches: the legislative, consisting of the bicameral congress; the executive, consisting of the president; and the judicial, consisting of the supreme court and other federal courts. articles four, five and six embody concepts of federalism, describing the rights and responsibilities of state governments, the states in relationship to the federal government, and the shared process of constitutional amendment. article seven establishes the procedure subsequently used by the thirteen states to ratify it. it is regarded as the oldest written and codified national constitution in force.