The answer is sexual reproduction in which the creation of offspring by fertilization consisting 2 haploid gametes come together to form a diploid zygote with a new genetic combination. The main difference between sexual and asexual reproduction is that asexual reproduction results in a genetically identical offspring whereas sexual reproduction results in a unique offspring in which offspring with a new genetic combination.
<span>Alleles are each of two or more alternative forms of a gene that are found at the same position in a chromosome. Traits on the other hand, are the characteristics that are defined by genes. So the combination of alleles for a gene is what manifests itself into a trait.</span>
The answer should be both
A biological system is a complex network of biologically relevant entities. ... Examples of biological systems at the macro scale are populations of organisms. On the organ and tissue scale in mammals and other animals, examples include the circulatory system, the respiratory system, and the nervous system. source: google