"In a particular case of secondary succession, three species of wild grass all invaded a field. By the second season, a single species dominated the field. A possible factor in this secondary succession was ."

A possible factor for the above is best described by the inhibition model. This is a model of succession that allows for early colonizers to modify their environment making it only conducive for them hence ensuring their survival. If this is done successfully, by the second season, of the the 3 species of  wild grass, only one will thrive in the field as a result of the phasing out of the other 2.

Explanation:

The inhibition model occurs as a result of the environment being modified by of the 3 species of wild grass by the 2nd season. This may have been as a result of it secreting biotoxins into the environment that destroys the other 2 wild grass, thus inhibiting their growth. This helps the organism thrive well during the 2nd season  

the calvin cycle has three stages. in stage 1, the enzyme rubisco incorporates carbon dioxide into an organic molecule. in stage 2, the organic molecule is reduced. in stage 3, rubp, the molecule that starts the cycle, is regenerated so that the cycle can continue

tsd is temerature dependent sex determination.

tsd: it is a type of environmental sex determination in which the temperature experienced during embryonic/ larval development (ambient temperature for development) determine the sex of the offspring.

crocodile displays the tsd where the ambient temperature of the developing egg determines the individual's sex. for example in the american alligator's eggs, incubation at 33 ºc produces mostly males, while incubation at 30 ºc produces mostly females. so if the american alligator's egg will get the ambient temperature (33 degree celcius)during embryonic development from egg, the offspring will be male and same for the female sex determination.