With sexual reproduction a sperm coming from the male must unite with the female egg. Both are needed for this kind of reproduction, and an offspring CAN'T be formed without both. Unlike asexual reproduction, the offspring of a mammal reproducing sexually is DIFFERENT from both parents, since the offspring is a combination of both the mother and the father.
An easy to remember example I use when thinking about what sexual reproduction is:
the formation of a human child. A mother with her egg and the father with the sperm is BOTH needed. If you think about siblings that come from the same parents (and therefore same gene pool) they are not all exactly identical to each other. Although they may have similar features, they look different and are NOT genetically identical
Therefor for your question the answer is D.
Hope this helped!
I really dont know the answer to this question! Try asking Goggle!
The answer might be lipid A
Ventilation systems are needed in a <span>multicellular organism to actually obtain oxygen and give out carbon dioxide. Without this ventilation system, it would be very difficult for multicellular organisms to survive. It has been also observed that surface diffusion is not enough for a multicellular organism to breath.</span>
