Answer:
Knowing the evolutionary relationships among species allows scientists to choose appropriate organisms for the study of diseases, such as HIV. Scientists are even using the principles of natural selection to identify new drugs for detecting and treating diseases such as cancer. Environmental change and isolation of groups of organisms play an important role in evolution. Environmental change is any change in an environment to which an organism must adapt. Change can be gradual, such as when mountains or deserts form, other species die out, or new species evolve.
Explanation:
A, B, C, E, and F are correct.
Answer:
A
Explanation:
I think this is the right answer? I'm not completely sure.
The alkali metals in group l of the periodic table all have a single electron in the outermost shell. These metals form covalent bonds with for example the halogens, which have 7 electrons in their outer shell.
When the alkali metal halide, such as KCl is dissolved in water, it dissociates into ions. The K atom loses the single electron, and therefore has a positive charge. In turn, the chloride atom gains the electron and becomes the negatively charged chloride ion.
