How is cactus adapted to survive in a desert?

How is cactus adapted to survive in a desert?

Cactus are adapted to survive in a desert as they have:

i. No leaves or have spiny leaves to prevent water loss through transpiration.
ii. Stem is modified in such a way that it performs photosynthesis and conserve water.
iii. Their roots go very deep into the soil for absorbing water.