Answer: More than 99 percent of all organisms that have ever lived on Earth are extinct. As new species evolve to fit ever changing ecological niches, older species fade away. But the rate of extinction is far from constant. At least a handful of times in the last 500 million years, 75 to more than 90 percent of all species on Earth have disappeared in a geological blink of an eye in catastrophes we call mass extinctions.
Though mass extinctions are deadly events, they open up the planet for new forms of life to emerge. The most studied mass extinction, which marked the boundary between the Cretaceous and Paleogene periods about 66 million years ago, killed off the nonavian dinosaurs and made room for mammals and birds to rapidly diversify
<span>Proto-oncogenes are genes that normally help cells grow. When a proto-oncogenemutates (changes) or there are too many copies of it, it becomes a "bad" gene thatcan become permanently turned on or activated when it is not supposed to be. When this happens, the cell grows out of control, which can lead to cancer.....Is this what you need ?</span>
Answer:
By getting rid of the deer the tree population increased, the reason behind this is because the deers ate the plants which made less trees 2. Under Choose organism, select the Mushroom.
Explanation:
DNA: adenine pairs with thymine
RNA: adenine pairs with uracil
The correct answer is: <span>oxygen is used up as algae is decomposed, reducing the amount available to other organisms. Algae require nutrients to grow, and it is well known that in many rivers, algal growth is limited by one particular nutrient, most often phosphates or nitrates. This means, as soon as there is a sizable input of nutrients into a river or lake, the algae population will grow exponentially. This dramatically changes the trophic status of a river or lake. However, the algal population will eventually exhaust the supply of nutrients, and the vast biomass of algae that grew over a short period of time will all die at the same time due to lack of nutrients. As you know, rotting organic matter uses up oxygen. This results in an anoxic aquatic environment that can kill all the other organisms living in that environment. </span>