C4 plants have evolved different photosynthetic mechanisms. these plants view available hint(s)
a) fix co2 into a four-carbon compound instead of a three-carbon compound
b) are adapted to living in cold, wet climates where there is no water shortage
c) do not fix co2 through the calvin cycle
d) conserve water more efficiently by shutting their stomata during the day
e) fix o2 instead of co2`

A) fix CO_2 into a four-carbon compound instead of a three-carbon compound

Explanation:

C4 plants have evolved different photosynthetic mechanisms. These plant

A) fix CO_2 into a four-carbon compound instead of a three-carbon compound

Some plants are called C4 plants because their first product of carbon fixation is a 4- carbon compound instead of a 3-carbon compound which is for most of the plants. These plant use this four carbon compound effectively to use them to concentrate CO_2 in the chloroplast (rubisco) so that the chloroplast is less likely to react with oxygen.

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.