The elements in each group have the same number of electrons in the outer orbital
That easy..............<span>21 one is your technical answer according to todays rules but scientist used to think it was only 20 so 20 would be your answer</span>
Answer:
All
Explanation:
You would need carbon dioxide to be able to sustain life forms such as plants, warm enough temperatures to allow the development of animals, (because they cannot be frozen), they would, of course, need oxygen to allow anyone to breathe, and finally liquid water to sustain healthy life, because we must hydrate that is necessary for survival.
Answer: One advantage is, well, the water. There’s plenty of it and it’s all around. Therefore, most aquatic plants do not need adaptations for absorbing, transporting, and conserving water. They can save energy and matter by not growing extensive root systems, vascular tissues, or thick cuticles on leaves. Support is also less of a problem because of the buoyancy of water. As a result, adaptations such as strong woody stems and deep anchoring roots are not necessary for most aquatic plants.
