Final answer:
Controlled and Safe Entry is the technique used to enter water safely when the depth and bottom conditions are unknown, by using feet and floating aids to detect obstacles.
Step-by-step explanation:
The type of entry that involves controlling the entry into water with unknown depth and bottom conditions, using feet and an aid to feel for obstacles below the surface, is known as a Controlled and Safe Entry. This technique is often used by swimmers, lifeguards, or anyone entering potentially hazardous water to prevent injuries from unseen underwater hazards. When performing a Controlled and Safe Entry, the individual usually extends one foot downward to probe for the bottom or any obscured obstacles while using a floating aid to help maintain balance and buoyancy.