It is because convergent evolution represents the independent evolution of similar features in species that don't have the same ancestor. In this case filamentous body forms evolved independently, but have the same function: an adaptation for a nutrition of decomposers.
Answer:
B. Directional selection
Explanation:
When natural selection starts to choose one phenotypes that is an extreme (as in, a really small neck or a really long neck), this is an example of <u>directional selection.</u> It makes sense for giraffes to have evolved this way, because the longer the neck, the more ably they can eat food from high branches. The more food they could get, the more chance of reproduction, the more "evolutionarily fit" they are.
Stabilizing selection is when national selection picks average phenotypes (like a medium-sized neck). Disruptive selection is when the extremes are both picked (like all the medium-sized neck giraffes die, and two different species start to emerge). Sexual selection is picking a mate based on traits. Clearly, those answers don't work here.
I'm not sure if I will answer the question you asked, as I many have interpreted it incorrectly. In natural selection, there must be variance in the gene pool, the total frequency of alleles in a population. Now, one of the organisms may have a gene that somehow helps them survive from the selective force much better compared to the others. If this does happen, over time the gene pool will narrow down to become just the genes of that organism that survived better in the first place because the rest would be taken care of by the selective force. So, the alleles and trait come from the first organisms that had the advantage over the others of its species.
The answer is stem cells, they consist of classes of cells
that are undifferentiated and are able to be classified them into types like
specialized cells. They consist of having two main sources that will help them
develop and mature, these main sources are called the embryonic stem cell and
the adult stem cell.
