For the answer to the question above, I think the answer is simply because <span>four legs characteristic is not special to mammals but the hair that is something more important and special characteristic of the mammals, that's why. I hope this helps
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Answer:
Migration
Explanation:
Birds have adapted to the changes in temperature (over generations) and know to migrate when necessary
The following five limiting factors would control the
population density of weeds;
<span>1.
</span>Supply and nutrients in the soil
<span>2.
</span>Presence/Absence of growth-restricting
substances such as pesticides
<span>3.
</span>The soil aeration and soil structure
<span>4.
</span>Moisture content in the soil.
<span>5.
</span>Biotic factors such as disease and pests
<span>6.
</span>Quality, intensity and duration of light
All matter whether solid, liquid, gas has a chemical formula or elemental symbol.
Filtration may work, there are many types of filters capable of filtering specific types if compounds.
.............Help on what?