Enzymes influence chemical reactions in living systems by a. Combining with excess hydrogen to form gaseous wastes
b. Affecting the rate (speed) at which reactions occur
c. Providing the substrate required for the reaction to occur
d. Absorbing water released when polymers are formed

I think its b. affecting the rate at which reactions occur

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.

i think it is dna, i'm not totally sure but i think it might be.