Water at 4 degrees centigrade has the highest density of all other water temperatures. This is why ice (whose temperature is below 0 degrees) floats on very cold water. This phenomenon is significant in the Artic and Antarctic where ice shelves float on cold ocean waters in the poles. Animals that live in these regions (such as seals and polar bears) use these ice shelves as hunting platforms.
One thing that separates us from the other animal classifications is that we have hair, everywhere! :D The next major difference is the fact that mammals don't lay egg's, we give birth to live creatures. Those are the 2 biggest things that distinguish us from them.
Hope I helped. :)
Answer:
Flatworms are beings that do not have a heart, veins, arteries, capillaries, hemolymph, or some type of circulatory fluid. Their circulation occurs between cells or intercellularly and they are responsible for transporting substances by diffusion from cell to cell.
Explanation:
Flatworms are considered multicellular eukaryotic organisms. This implies that in their cells they have a cellular nucleus, in which the DNA is contained, structuring the chromosomes. Likewise, they are made up of several types of cells, each one specialized in a specific function. They lack a structured circulatory system as such. Because of this they do not have specialized structures such as a heart or blood vessels, however, the circulation of certain substances is established between their cells. This is done thanks to the diffusion process. Substances pass from one cell to another through this process.This does not apply to all flatworms, since in some species of bog and digenae there is a certain organization and some very small conducting vessels known as the endolymphatic system, the which forms a kind of plexus in the parenchyma.It should also be noted that some species do not even have a digestive system, being the digestive tract the one in charge of digestive functions and the distribution of the nutrients they receive.
<span>Constructing recombinant DNA or rDNA scientists
should combine both DNA from two different species. Based on study, rDNA
is possible if both DNA that should be combined should have the same chemical </span><span>structure.
Most o the DNA do have the same structure they only differ in nucleotide
sequence. </span>
