Because science involves a lot of replication to confirm results. That means without the systems, it would take a long time to get the results right.
Answer:
By pulling down rocks and particles.
Explanation:
For example, in a cliff, where rocks are being pulled down by gravity. Their particles and small pieces of rock are forced to fall apart, slowly eroding down any rock or sediment.
From: https://answers.yahoo.com/question/index?qid=20111123203903AA4eLha
1. Less trash to landfill. More recycled items = savings to production costs of new items
<span>such as aluminum, glass, cardboard. </span>
<span>2. Most insects have particular predators such as a specific animal or bird that eats them as a major or sole portion of their diet. </span>
<span>3. Do not plant 100% of the same plants and trees across the area. </span>
<span>Do not harvest all of a species during a normal growth cycle. If a tree takes 50 years to grow to harvest size, schedule cuttings to avoid extinction of that tree within the area.</span>
Because as humans grow bigger, so does there brain. So the smaller you are, the smaller your brain.
Hope this helped!
-Edge
