What adaption allows the cactus to thrive ? needles to prevent dying out ..or deep roots to absorb ground water?

The answer would be deep roots to absorb ground water.

Cacti are found in deserts, which do not receive much rain.  Cacti, like all plants, need water to live so deep roots would help the cactus obtain water.

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the "power" of a lens is its resolution power, or its ability to distinguish between to closely located points. with the low power lens, it is likely you will see the rough form of the hay and maybe some movement of dots around the hay. however, when observed with the high power lens, the detailed features of the hay become visible and the microbes being grown are more clearly visible.

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