Epidemiology

question 5

Multiple Choice

Epidemiology:

• A) is a science that studies the poisonous effects of chemicals.
• B) explains the association between learning disabilities and exposure to lead-based paint at the cellular level.
• C) helps nurses understand the strength of the association between exposure and health effects.
• D) is a method for tracking the prevalence of health outcomes.

---

Definitions:

Sieve Tubes

A series of sieve tube elements placed end to end to form channels for nutrient transport in plants.

Vessel Members

Components of the xylem tissue in plants that help conduct water and minerals from the roots to the rest of the plant.

Companion Cells

Plant cells that aid in the transport and regulation of nutrients within the phloem.

Pits

Small depressions or cavities on a surface, often used to describe features in plant or geological structures.