Caseation necrosis refers to an area where: 1) cell proteins have been denatured.2) cell are liquefied by enzymes.3) dead cells form a thick cheesy substance. 4) bacterial invasion has occurred.

The correct answer is 3) dead cells form a thick cheesy substance

Explanation:

Caseation necrosis refers to the necrosis which reflects the occurrence of the cell death where dead cell material shows the crumbly cheese like appearance. It usually occurs in lungs as well as kidneys. Example : tubercular infections. Main reason is caused by syphilis & fungi. When hilar lymph nodes are affected with TB, the appearance is from cheezy tan to white. Thats why this type of necrosis is called mixture of both necrosis( liquefactive&  coagulative necrosis). Eg.Ghon complex in lungs