Answer: 20.2
Explanation:
Mass of isotope 1 = 20
% abundance of isotope 1 = 90.5% = 
Mass of isotope 2 = 22
% abundance of isotope 2 = 8.0% = 
Mass of isotope 3 = 23
% abundance of isotope 3 = 1.5% = 
Formula used for average atomic mass of an element :
![A=\sum[(20\times 0.905+(22\times 0.08)+(23\times 0.015]](https://tex.z-dn.net/?f=A%3D%5Csum%5B%2820%5Ctimes%200.905%2B%2822%5Ctimes%200.08%29%2B%2823%5Ctimes%200.015%5D)
Therefore, the average atomic mass of the element is 20.2.
Subscripts cannot be changed because they are the ratio of the amount. And as we know, in a chemical equation/reaction, mass cannot be created nor destroyed. Therefore, we cannot change subscripts, however, we could change coefficients. <span />
Answer:
C). The structures in the cell work together to perform its life functions.
Explanation:
Unicellular organisms are characterized as organisms that are able to perform all the life functions through a single-cell. The third statement correctly elaborates how '<u>single-celled organisms carry out these life functions by cooperatively employing the structures lying inside the cell</u>.' The first option is incorrect as it talks about multi-cells which doesn't even exist in unicellular organisms. While the second option is wrong because there are no tissues formed of single-cell. The last option is incorrect as the specialized cells perform different life functions in multi-cellular organisms. Thus, <u>option C</u> is the correct answer.
Answer: A
0 degrees and 101 kPa are the conditions that describe the standard temperature and pressure. When expressed in K, the standard temperature 0 degrees equals 273.5 K. Also the standard pressure 101 kPa equals 760 mmHg or 1 Atm.
