The answer is carbon dioxide. im 100 percent this is right<span />
Answer:
The rift valley formed when the crust pulled apart.
Explanation:
The statement that best describes how the Great Rift Valley in Africa formed is that they formed when the crust pulled apart.
- This is geologically known as divergence.
- The Arabian plate and the Nubian/Somali plate are divergent plates.
- They are currently moving apart and away from each other.
- This creates a crack on the earth which is what formed the rift valley in Africa.
- Along such margins, earthquake activities are prominent.
Answer:
In an ancestral elm species, mutations gave rise to the phenotypic trait "winged-seeds". Subsequently, selection favored elm plants with winged-seeds that diverged over time to become a separate species
Explanation:
A mutation is a genetic change in the DNA sequence. In general, mutations have a negative impact on the fitness of the individual (i.e., mutations are generally deleterious) and therefore they disappear from the population. However, there are situations where mutations are beneficial and confer an adaptive advantage, thereby increasing their frequency in the population. In this case, mutations associated with the formation of winged-seeds conferred an adaptive advantage (i.e., higher seed dispersal capacity) to individuals who had this phenotypic trait, thereby these individuals had more chances to reproduce and pass their genes to the next generation. Eventually, Elm plants with winged-seeds accumulated sufficient genetic differences to prevent interbreeding, leading to the formation of a separate species.
There is no context so I will just explain what a constant is:
In an experiment following the scientific method, a constant is a variable that cannot be changed or is purposely not changed during the experiment.
An example would be:
If a researcher wanted to study the effects of temperature on the growth and development of garden snakes, the experimental variable for the experiment would be temperature. All other variables would need to remain consistent to avoid invalid data. The size of the cage, amount of light, food and many other variables would need to remain constant to ensure accurate results and a valid study. Those variables are constants. Some variables are not under a scientist's control, but are still considered to be constants. These constants are called universal constants and include gravity, the speed of light and electronic charge. Universal constants do affect experiments but will be constant through an experiment without being controlled by the scientist.
