Most fresh water fish are hypertonic, meaning their body cells contain more salt than the surrounding water. Since osmosis should push water into their cells, why don't they explode?
a) They urinate a lot, so the water does not build up.
b) They don't drink any water because they get so much from osmosis.
c) Their cells have adapted to absorb salt.
d) They have adapted to live with high osmotic pressure.
e) All of the above
Question 2
Why do most fish and marine mammals have the same torpedo-like, streamlined shape?
a) A streamlined shape presents a greater surface area-to-volume ratio, which allows easier regulation of internal heat.
b) If you are going to move through a substance, like water, it is necessary to have a head and eyes at one end and a tail at the other.
c) Streamlining looks better to the opposite sex, so it leads to greater reproduction.
d) The streamlined shape minimizes energy expended to move through the water.
e) They can swim faster with streamlined shapes.
Water striders serve as a model organism for the study of sexual conflict between males and females.
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