Judging from their basal metabolic rates (an indicator of thyroid function), categorize the rats as hypothyroid (low thyroid levels; BMR below 1600), euthyroid ("good," or normal, thyroid levels; BMR = 1650-1750), or hyperthryoid (high thyroid levels; BMR above 1800). The normal rat is:.a. hypothyroid. b. euthyroid. c. hyperthyroid.

Option b (Euthyroid) is the correct option.

Explanation:

Its normal rate will be:

⇒  

The other choices have no relation with the particular situation. So the argument presented however is the right one.

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.

c. live where it’s cold and icy