Which of the following is a characteristic of robust scientific knowledge? A. It is frequently re-examined.
B. It is rarely subjected to arguments.
C. It has been disproven several times. .
D. It develops over a short duration of time.

d: the voltage of the secondary coil is less than that of the primary coil.

im not suree sorry if wrong

gas

explanation:

smoke is the matter of a gas

percent abundance for cu-63 can be shown as:

63 x + 65 (1-x) = 62.9296

65 - 62.9296 = 2 x

x = 1.035

thus, percent abundance for cu-63 is 1.035

percent abundance for cu-65 can be shown as:

63 x + 65 (1-x) = 64.9278

65 - 64.9278 = 2 x

x = 0.0361

thus, percent abundance for cu-63 is 0.0361

the mass spectrum of cu-63 showing the intense peak as, this isotope is found in nature more abundantly around 92.38 % in comparison to cu-65 which is found 62.58 % naturally