Algae are photosynthetic, but they are also unicellular organisms (Euglena) and shares some of the common features with plants as well as animals. They move like animals and perform photosynthesis like plants. Therefore, they are classified into Protists, and not the Algae. Their most features resemble the non-photosynthetic protozoa, and not plants, and therefore, are put into the Protista.
They also lack a cell wall, which is a feature of plants.
Some scientists advocate their classification in plants because of their sexual mode of reproductiona, and formation of spores.
Answer:
The system that moves blood throughout the body.
What do you mean <span>It has been observed that certain species of insects which had not previously caused significant harm have become serious pests. the best explanation for this phenomenon is that the pesticide killed off predators which had previously held this species in check. a mutation occurred in the species. the pesticide increased the vigor of the species. was able to be used by the pest as an additional food source is also a reproductive for some insect species. </span><span />