Answer:
Xe
Explanation:
Cs and Na are solids in room temperature while F and Xe are gases.
The number of electrons in the outermost shell of an atom will determine its reactivity. Out of the gases given Xe and F, F ( the most electronegative element) posses 5 valence shell electrons which makes it highly reactive while Xe which is a noble gas posses 8 valence shell electrons which makes it less reactive compared to many elements.
Answer:
<em>The principle of common descent states that all organisms in the world exist because of a common ancestor which gave rise to all the life seen on Earth. The organisms which are more closer to one another might have a common ancestor in the near past as compared to other organisms. The organisms which share distant common ancestors have less common characteristics. This principle has led us to form the basis for the formation of evolutionary biology. </em>
Answer: respiratory system
Explanation:
The respiratory system is the network of organs and tissues that help you breathe. It includes your airways, lungs and blood vessels. The muscles that power your lungs are also part of the respiratory system. These parts work together to move oxygen throughout the body and clean out waste gases like carbon dioxide
