Cholera spreads through
Polluted air
Mosquito bite
Polluted water
Dog bite

it spreads through polluted water.

Explanation:

Cholera is a water-borne disease spread through polluted and stagnant water bodies. It is caused by a bacteria named Vibrio cholerae by the help of the vector 'Water'.

Hence it is advised to consume boiled and purified water, clean the nearby water bodies and not letting them go stagnant. Always preferred: Hygiene and Sanitation.

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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.