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.
When less energy is needed for the reaction, more molecules will possess enough energy to get over the barrier. Reducing the barrier is the job of catalysts. They alter the situation to reduce the barrier to reaction. Enzymes are a subset of catalysts; they work on biological reactions.