This is an example of inter specific competition. Blue birds and blue jay are living in the same small wooded area. Both of the birds lives in their, however only the stronger one will remain. And since the blue jays are very aggressive, it eventually take over the nests of the blue birds.
<span>This would be a positive reinforcer. These are things like rewards and bonuses that will cause the subject to want to continue the rewarded behavior. The reinforcer does not need to be financial or even tangible. Positive comments and approval can be reinforcers that strengthen associated behaviors.</span>
Increasing the pressure on a certain amount of crystals and/or rock can cause all of those crystals and/or rock to be smashed and stuck together due to high temperature (which helps melt and stick it all together), which causes the formation of a mineral.
The most common cause is the accuracy of the measure instruments. And the observation of operator is also an important factor. That's why one measurement should do three times and use the average.