Answer:
HPE (health population and the environment) is a multidisciplinary subject
Step-by-step explanation:
Multidisciplinary mean from different disciplines but working together. In education or academia health, population and environment have different origins but when combined together make a multidisciplinary subject. Health is an important discipline in our lives but environmental factors also influence our health. Similarly, social factors like more population impact the environment. So HPE is a multidisciplinary subject and these three disciplines are interconnected somehow because we can not just study the environment without considering the effects on people or vice versa.