How does the cactus develop or grow?

As with any plant, the cactus depends upon the water, minerals, and dissolved nutrients that its roots take in from the soil, or from the air if they're air hanging epiphytes. The cactus also depends upon the sunlight that directs its rays towards the cactus stem, for the photosynthetic interaction with water, minerals, and dissolved nutrients. And the cactus depends upon the energizing photosynthetic byproducts for carrying on life sustaining activities. Additionally, the cactus depends upon the proper functioning of buds and meristems to grow upwards.