Answer:
Explanation:
Active cellular transport:
- It is the movement of molecules against the concentration gradient (from low concentration to high).
- Active transport requires expense of energy supplied by ATP.
- It is a rapid way to transport of large sized molecules.
Passive cellular transport:
- It is the movement of molecules along the concentration gradient (from high concentration to low).
- Passive transport does not require expense of energy.
- It is a slow process and small sized molecules get transprorted.
Answer:
The above paragraphs describes that how salt- and fresh-water fish regulates their osmoregulation. Hence, the correct answer would be c. have adapted to deal with osmosis.
Osmosis is the process by which solvent's molecule move from region of low concentration (hypo-tonic) to the region of high concentration (hyper-tonic) through a semi-permeable membrane.
In sea-water fishes, the body fluids are hypo-tonic to the surrounding water and thus water is kept moving out of their gills. In order to prevent the excess water loss they need to drink water constantly and excrete concentrated urine.
In contrast, fresh-water fishes body fluids are hyper-tonic to surrounding water and hence, water keeps entering in their body through gills. So, in order to prevent excess dilution they absorb salt from surrounding with the help of gills and also their bodies reabsorb salt from urine.
A. They are consumed by the reactions they catalyze
