Answer:
D
Explanation:
Elements in the same group (vertical columns) have the same number of valence electrons. These elements behave similarly because they will either give up or take the same number of electrons to fill their valence shell. Since potassium has 1 valence electron, it will most likely give up one electron. Out of all of the answer options, the only element that is in the same group as potassium is francium.
<span>In the 19th century, scientists realized that gases in the atmosphere cause a "greenhouse effect" which affects the planet's temperature. These scientists were interested chiefly in the possibility that a lower level of carbon dioxide gas might explain the ice ages of the distant past. At the turn of the century, Svante Arrhenius calculated that emissions from human industry might someday bring a global warming. Other scientists dismissed his idea as faulty. In 1938, G.S. Callendar argued that the level of carbon dioxide was climbing and raising global temperature, but most scientists found his arguments implausible. It was almost by chance that a few researchers in the 1950s discovered that global warming truly was possible. In the early 1960s, C.D. Keeling measured the level of carbon dioxide in the atmosphere: it was rising fast. Researchers began to take an interest, struggling to understand how the level of carbon dioxide had changed in the past, and how the level was influenced by chemical and biological forces. They found that the gas plays a crucial role in climate change, so that the rising level could gravely affect our future. (This essay covers only developments relating directly to carbon dioxide, with a separate essay for Other Greenhouse Gases. Theories are discussed in the essay on Simple Models of Climate.)</span>
Answer:
<span>The energy involved in endothermic and exothermic reactions is Heat.
Explanation:
In Endothermic Reactions the energy required to break the bonds is greater than the amount of energy released on bond formation. This required excess energy is absorbed from surrounding in the form of heat. Hence, the temperature of surrounding drops.
While, </span>In Exothermic Reactions the energy required to break the bonds is less than the amount of energy released on bond formation. This excess energy is released to the surrounding in the form of heat. Hence, the temperature of surrounding rises.
Answer:
Organ
Explanation:
Cells work together to make tissues, tissues work together to make organs, organs works together to make the organ system, and the organ system works to help the organism stay alive and do all of the physical stuff._.
Answer:
Incomplete combustion of carbon occurs if enough air is not available to convert all of it to carbon dioxide, and in such as case carbon monoxide is formed by the addition of half the amount of oxygen as is present in carbon dioxide, to the carbon atom, namely, CO instead of CO2.
Explanation:
