The difference between the two students that we know of is that they used a different meter stick. So the difference would be best attributed to the different tools they used.
Note, this is quite a huge difference. It's likely that one of the sticks, or both, are quite defect.
Properly identifying each species.
Accurately recording his findings.
Not interfering with ecosystem while studying the birds.
Answer:
The answer is c.
Explanation:
Age structure data can include all of these aspects except for c I believe.
When sound waves hit a solid surface they either reflect, refract, or absorb.
Echo's are caused by the reflection of sound waves.
