In an automobile's catalytic converter,
several reactions occur to reduce the amount
of carbon monoxide, nitrogen monoxide, and
unburned hydrocarbon pollutants that are
released in the exhaust gases. the exhaust
gases pass over a ceramic honeycombed
structure with a large surface area plated with
the catalysts platinum, rhodium, and
palladium before they leave the tail-pipe. in
spite of these safeguards, however, studies
have shown that most of the pollutants
released from a car happen during the first
one to two minutes after the car is started,
and then decrease significantly after that.
which factor affecting reaction rates is
responsible for this phenomenon?
a presence of a catalyst
b temperature
c concentration of reactants
d surface area

The most of the pollutants (carbon monoxide, nitrogen monoxide and unburned hydrocarbons) are released from the car during the first one to two minutes after the car is started, and then decrease significantly after that, due to increasing the temperature which supply the system by heat that required to oxidize the released gases by increasing the rate of the chemical reaction.

Then, the correct answer is the temperature  (B).

the leaf is an organ of a typical plant, and the main functions are to complete photosynthesis and allow the plant to exchange gas, just like how we have the respiratory system. leaves have the stomata, which collects maintains co2 and o2 levels. this is necessary for cell metabolism. the leaf also collects sunlight using chloroplasts. succinctly, leaves own a pivotal role in sustaining plant life.