Explanation:
Given that,
Distance 1, r = 100 m
Intensity, 
If distance 2, r' = 25 m
We need to find the intensity and the intensity level at 25 meters. Intensity and a distance r is given by :
.........(1)
Let I' is the intensity at r'. So,
............(2)
From equation (1) and (2) :
Intensity level is given by :
, 
dB = 32.96 dB
Hence, this is the required solution.
The observable universe<span> is a spherical region of the </span>Universe, <span>comprising all matter that can be observed from Earth at the present time, because light and other signals from these objects have had time to reach Earth since the beginning of the cosmological expansion.
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Off the top of my head, I only know 9 and 11, so I'll answer those two.
9) A heterotroph is an organism that relies on other organisms for food/energy
An autotroph can produce its own food from inorganic compounds (light)
11) Vascular plants have specialized tubes for transporting nutrients
Nonvascular plants do not have such tubes and are simpler
