Feathers<span> vary considerably in structure and </span>function<span>. </span>Contour feathers<span> form most of the surface of the bird, streamlining it for flight and often waterproofing it. The basal portion may be downy and thus act as insulation.
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I’m positive that the answer is B
The correct answer is B.
The cell membrane is a two-layer lipid membrane that surrounds and protects the cell. It allows only certain molecules to enter and leave the cell, that's why we call it semi-permeable. The membrane is permeable only for small,uncharged molecules which enter and leave in the process of osmosis. All other types of molecules require a special transport protein or a channel in order to be transported trough the cell membrane.
Answer:
all living beings are made up of cells.
Cell is the most basic unit of life.
All cells must come from pre-existing cells
Explanation:
those are statements from the cell theory
<span>Cellulose is a lot stronger than starch. Starch is practically
useless
as a material, but celluose is strong enough to make fibers from, and
hence rope, clothing, etc. Cellulose doesn't dissolve in water the way
starch will, and doesn't break down as easily.
</span>Your body contains
enzymes that break starch down into glucose to fuel your body. But
we humans don't have enzymes that can break down cellulose.
