Fossilization is a rare process, the vast majority of deceased organisms disappear without leaving a trace. Fossilization of an organism requires a unique set of circumstances so that it doesn’t just decay without a trace. These conditions include:

Some plants and animals are too small to be preserved as fossils.
Sediment deposition and accumulation is necessary for fossilization.
Animals with hard shells and skeletons are better represented in the fossil record.
High oxygen concentrations are required to prevent decomposition.
Most fossils are formed when a plant or animal dies in a watery environment and is buried in mud and silt.

Read the article about the fraser river, one of the most important rivers in canada. what is the most important species of fish in this river? why are the numbers of these fish declining?

Directions you probably already know that people have different ways to organize their ideas. some people make lists or outlines, some draw pictures, while others may combine these two methods. experiment with different note-taking techniques to find the one which works best for you. one common note-taking technique is webbing. webbing uses the sizes of circles to indicate the importance of items. lines are used to indicate the relationships between items. the example below is based on the information presented in a previous lesson. notice that the circle for "geography is" appears at the center of the web. it has larger than the circles that surround it. the "geography " circle is surrounded by smaller circles of earth's atmosphere, earth's climate, earth's surface. notice the lines that connect these items to the concept of geography. notice that the circles surrounding atmosphere are smaller. also observe that the lines that connect the items and indicate the relationships between the items. webbing will you capture the most important points in your lessons. beginning with lesson two, geographic tools: globes and maps, use webbing to take notes on the important information in this unit. hint: it will be easier to complete this project if you take your notes after completing each lesson.

If you were a casual recreational hiker with young children, which of the following trails would be least strenuous for a leisurely family outing? a. merced lake trail b. mirror lake loop trail. c. tenaya lake and tuolumne meadows trail d. el capitan trail