There are two main Types of Trees based on their leaves, deciduous and evergreen; 1  Deciduous trees are trees whose leaves loose their green coloring and turn orange, red or brown before they are shed at the end of the growing season, generally in autumn. 2  Evergreen trees carry their leaves throughout the year.
A catalyst is a chemical species that alters the rate of a chemical reaction without undergoing any type of change. Such catalysts that slow down a reaction are called negativ â¦ e catalysts or poison.
As the name implies, catalytic converters contain catalysts. A catalyst is something that participates in the reaction, lowering the activation energy and hence increasing the reaction rate. Catalysts are not consumed in the reaction. (See the tutorial, Drug Strategies to Target HIV: Enzyme Kinetics and Enzyme Inhibitors for a review of how enzymes function as catalysts.)