The leaf is a flat organ composed of
two layers of photosynthetic cells sand-
wiched between the epidermal, or outer,
layers. the epidermal layers are coated
with a waxy covering called the cuticle,
which prevents the loss of gas and water.
tiny holes, called stomata, provide open-
ings for the entry of carbon dioxide and
the exit of oxygen.
2. based on the information above,
the leaf "breathes" through its
(1) photosynthetic cells
(2) veins
(3) cuticle
(4) epidermal layers
(5) stomata

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.

d. changes in climate and historical records

hope this

answer australia and antarctica;