<span> Definitions, theorems, and sample problems</span>
A biogeochemical cycle is a pathway by which a chemical substance moves through both biotic and abiotic compartments of earth
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!
Food availability, space, water, and environmental conditions
Covalent bonding occurs when pairs of electrons are shared by atoms. Atoms will covalently bond with other atoms in order to gain more stability, which is gained by forming a full electron shell. By sharing their outer most (valence) electrons, atoms can fill up their outer electron shell and gain stability
