Psychologists are interested in people's behavior and their mental processes. Psychologists believe that:

behavior is impacted by environment, but not by a person's physical state.
behavior is affected by a person's mental and physical state, but rarely by his or her environment.
a person's physical state, mental state, and the empirical evidence impact his or her behavior.
a person's physical state, mental state, and environment influence his or her behavior.

Im confused, please help!

This one is correct.

a person's physical state, mental state, and environment influence his or her behavior.

The correct belief among psychologists is that a person's physical state, mental state, and environment influence his or her behavior. Psychologists take into consideration all three aspects when studying human behavior and mental processes.

To arrive at this understanding, psychologists conduct empirical research using various methods such as surveys, experiments, and observations. This research involves gathering evidence to test hypotheses and draw conclusions about how different factors impact behavior.

By considering a person's physical state, psychologists recognize that physiological factors like genetics, brain structure, and overall health can influence behavior. For example, neurological disorders can affect a person's cognitive functioning and behavior.

Psychologists also consider a person's mental state, recognizing that thoughts, emotions, beliefs, and motivations can have a significant impact on behavior. Mental health conditions, such as depression or anxiety, can affect one's behavior and interactions with the environment.

Finally, psychologists acknowledge that the environment plays a crucial role in shaping behavior. The environment includes the physical setting in which a person lives, societal and cultural influences, family dynamics, and social relationships. Environmental factors can shape behavior through learned behaviors, social norms, and the availability of resources.

So, in summary, psychologists believe that a person's physical state, mental state, and environment all interact and influence behavior. This perspective recognizes the complex and interconnected nature of human behavior.