vertebrate physiology

[Nicolodn]

These are from a practice exam, I've already narrowed down my answers, these are the ones I'm not sure about.
THANKS.

The tissue type repsonsible for protection of the body from the external environment?
-skin, epithelium or integument?

I am thinking epithehelium
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Which best explains why long bones are hollowin themiddle?
- lighten them, Wolff's law (absence of load)?
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Which about collagen is FALSE?
- formed by macromolecular assembly of procallagen, produced by enzymes, or its slight crimp give it elasticity independent of elastin?
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Which is false?
- primary cell in fibrocaritlage is fibrochondrocyte or , primary celll type in skeletal muscle is myofibre?
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Which tissue best resit tensile pure force?
- tendon, muscle elastic cartilage or fibrocartilage?
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Which does not describe how animal reduce heat loss in cold environment?
- brown adpose tissu, or decrease body temp or countercurrent mechanisms?


THANKS.

[JackBean]

- will it be the first layer or some of the in bottom?

- also the strength

- I think the first one(you know why?)

- all primary cells are called -blasts, so any should be correct

- I think tendon

- you know what function of brown adipose tissue function is?