Speciation is the adaptive divergence and gradual that leads to two different species.
Reproductive isolation results in speciation when the processes of evolutionary mechanisms, physiological and behaviours are collected.
Mechanism of reproductive isolation helps in preventing members of different species from producing offsprings. A zoologist is a classified way of reproductive isolation whereby it(zoologist) is classified to the mechanism of reproductive isolation into two categories
(i) Pre-zygotic. This one acts before fertilization or before mating when it comes to animals.
(ii) Post-zygotic. It acts after fertilization.
The mechanisms appear I species which are genetically controlled and whose geographic distribution overlaps or are separated.
The three main worm phyla are flatworms, roundworms, and segmented worms. Roundworms have a digestive tube that has two openings. Segmented worms have a closed circulatory system in which blood is enclosed in blood vessels. These are important steps in the evolutionary development of animals.
Answer:
Cell size is limited by a cell's surface area to volume ratio. A smaller cell is more effective and transporting materials, including waste products, than a larger cell. Cells come in many different shapes. A cell's function is determined, in part, by its shape.
