How do plant roots "know" to grow downward? this is a plant response called
a) gravitropism.
b) hydrotropism.
c) phototropism.
d) thigmotropism.

The correct answer would be A) gravitropism

Gravitropism or geotropism refers to the differential growth of a plant in response to the gravitational pull.

For example, roots show positive geotropism, that is, they grow in direction of gravitational pull.

In contrast, shoots show negative geotropism, that is, they grow in opposite direction as compared to the direction of gravitational pull.

burning of wood and coal

explanation:

the panel also concluded there's a better than 95 percent probability that human-produced greenhouse gases such as carbon dioxide, methane and nitrous oxide have caused much of the observed increase in earth's temperatures over the past 50 years.

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.