A tap root is a primary root that grows vertically downward and is thicker than other roots. It serves as the main anchor for the plant, allowing it to access deeper soil layers for water and nutrients. This type of root system is commonly found in plants like carrots and dandelions, which rely on their tap roots for stability and sustenance. In addition to providing support, tap roots can store energy and nutrients, helping the plant survive adverse conditions. They are essential for the growth of many trees and shrubs, contributing to their overall health and resilience in various environments.