Dragonflies are most closely related to damselflies. Damselflies are smaller, slimmer, and most of them fold their wings along their body when they are resting.
Darwin lived in a time where natural selection was a strange theory among scientists and researchers. This was especially true when other researcher Lamarck argued that organisms passed on helpful traits to their offspring, that they magically could form a new trait to adapt to their environment and then pass it onto their offspring. For example, if a giraffe was too short to reach food, it would grow a larger neck in its lifetime and then pass that trait onto its offspring. Darwin argued that, through the process of survival of the fittest, that short giraffe would die off and never receive the chance to pass on its shortness to future populations. Thus, taller giraffes would survive— they can reach food, shorter giraffes can’t— and the short genes would disappear. The fact that Darwin was introducing a new theory that nobody was used to at the time was peculiar, so he had few people on his side until long after his observations.
Another problem Darwin had was the lack of technology. To travel, Darwin would have to use boats to reach far away places, and of course, this took time.
The final problem Darwin had was the extra time it took for evolution, a process that can take up to millions of years. Evolution didn’t occur over night— it took time for Darwin to conduct experiments, observe, conduct them again, come to a conclusion, and so on.
Hope this helped a little!
They are involved in a chemical digestion.
Chemical digestion involves breaking down the food into simpler nutrients that can be used by the cells. It begins in the mouth when food mixes with saliva which contains enzyme salivary amylase that breaks down carbohydrates. It also occurs in the stomach where HCl and pepsin forms chyme and small intestine especially in the duodenum.
The cardiovascular system is a system of organs that facilitates the circulation of blood to all parts of the body. Blood is required to reach all living cells as the blood carries essential elements for cell life and regulation, such as nutrients, amino acids, electrolytes,oxygen and hormones. The blood also has a role in maintaining body temperature, fighting diseases, maintaining a stable pH and maintaining homeostasis. The blood also carries carbon dioxide away from the cells. The cardiovascular system consists of a network of arteries, veins and capillaries, as well as the heart, which acts to pump blood around the body, Blood leaves the heart via arteries and return via veins. The lymphatic system transports lymph, typically at a much slower rate than blood. The lymphatic system is an important part of the immune system. Unlike the cardiovascular system, the lymphatic system is not a closed system. The cardiovascular system processes a lot of blood each day through capillary filtration, which separates the blood cells from the plasma. Not all plasma is re-absorbed into the blood vessels, and the lymphatic system is responsible for returning the remaining plasma to the cardiovascular system. <span> </span>
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the opening of the double helix and separation of the DNA strands, the priming of the template strand, and the assembly of the new DNA segment.