Answer: The oxygen content at the source of the streams or rivers is higher as compared to the mouth of the river. Consequently, the organisms which require more oxygen tend to find at the source of the rivers whereas the organisms which require less oxygen tend to find at the mouth of the river.
Explanation:
Males tend to determine the sex of the baby depending on whether sperm is carrying and X or Y chromosome. An X chromosome combines with a mothers X chromosome to make XX (Girl). A Y chromosome from a male will combine with a mothers X chromosome to make an XY (Boy).
Males always pass on the Y chromosome
C hydrosphere, lithosphere, biosphere
