The mass of an object is describes in D. Grams.
Isotopes are atoms of the same element that have different masses. The relative atomic mass (am) is a weighted average that takes into account the abundance of each isotope. We can calculate the relative atomic mass using the following expression.

where,
- abi: percent abundance of each isotope
For Gallium,
[1]
where "x" and "y" are the unknown abundances.
We also know that the sum of both abundances must be 100%.
x + y = 100
y = 100 - x [2]
If we replace [2] in [1], we get

Then, in [2]
y = 100 - x = 100 - 20.5 = 79.5
In conclusion, Ga-69 has an abundance of 20.5% and Ga-71 has an abundance of 79.5%.
You can learn more about isotopes in: brainly.com/question/21536220?referrer=searchResults
C. Not each element has a known neutron number
Answer:
Ethical concerns affect scientific research by adding boundaries to what can and cant be experimented on. An example is that its socially unacceptable to experiment on humans because its considered wrong and horrific, even at the expense of learning more about human nature and/or the human body.
Sucrose; C12H22O11
C9H8O4; acetyl salicylic acid
H2O2; hydrogen peroxide,
NaOH; sodium hydroxideExplanation: