How cactus protect themselves from enemies?

Answer 1

Its modified leaves are the most obvious defense mechanisms of cactus plants. They take the threatening form of thorns, spines, spikes, quills, prongs, needles, hairs, or bristles. They're particularly threatening when they have barbed ends that quickly become, and stubbornly remain, embedded in the flesh.

Another defense mechanism is sheath that encases the stem. It's thick and covered with a glossy, leathery or waxy surface that stops water loss and disperses sunlight. The cactus thereby is protected against drying out on the inside and burning up on the outside.

Still another defense mechanism are the guard cells. They're found on either side of the openings to the breathing pores, or stomata. They close to keep in water, and open to let in necessary gases from the atmosphere.

Answer 2

It protects it self with its spikes so no animal would eat them, then in the desert its roots reach deep underground where there should be an underground stream giving it an endless supply of water.

Answer 3

Some cacti have spines, others contain alkaloids that can make the offending party quite uncomfortable.

Answer 4

By being spiky, bristly and difficult to eat.