A forest has many trees and bushes that produce nuts. This is a major food source for many species, including a particular bird. Birds of this species have a variety in beak shapes ranging from long and pointy to short and hard. The birds with short and hard beaks are able to eat the nuts better than the birds with long and pointy beaks. What do you expect to happen to this population of birds over time, in terms of what you know about evolution? Address all four principles of natural selection in your explanation.

There are four principles at work in evolution—variation, inheritance, selection and time. These are considered the components of the evolutionary mechanism of natural selection. After a while the birds will get old and their beaks will get weaker, eventually they will die, when there is a shortage of food they will start harming each other in order for it, that’s selection.

organisms that lack symmetry are called asymmetrical and belong to phylum porifera/sponges.

organisms with specialized stinging cells belong to phylum cnidaria. stinging cells are called cnidoblast cells.

cnidarians show two morphological forms : polyp (sessile) and medusa (mobile)

filter feeding is observed in porifera members.  

alternation of generation is observed in coelenterata or cnidaria. there is alternation of asexual polyp form and sexual medusoid form. it is also referred as metagenesis.

the answer to you question is   jet streams