Final answer:
Stress management lectures represent primary prevention, aiming to prevent diseases by reducing risk factors like stress before they occur, unlike other options which are forms of secondary or tertiary prevention.
Step-by-step explanation:
Primary Prevention in Health
The activity that exemplifies primary prevention from the options given is stress management lecture. Primary prevention aims to prevent diseases or injuries before they occur. This can involve altering behaviors that can lead to disease such as smoking, promoting resistance to disease, or dampening the impact of a disease-causing agent. A stress management lecture helps individuals learn ways to reduce and manage stress, which is a risk factor for many conditions including cardiovascular disease. It does not involve the treatment of an existing disease but rather seeks to prevent diseases that can be exacerbated by stress.
On the other hand, blood pressure screening is a form of secondary prevention as it involves detecting a disease early and preventing its progression. Beta blocker therapy and enrollment in cardiac rehabilitation are examples of tertiary prevention, which aims to soften the impact of an ongoing illness or injury that has lasting effects.