How do living things obtain oxygen
2 answers:
You might be interested in
Answer:
b
Explanation:
The correct answer would be 45.
Assuming that the 10 soils are each represented by A, B, C, D, E, F, G, H, I, J.
A can combine with 9 others as: AB AC AD AE A F AG AH AI AJ
B can combine as: BC BD BE BF BG BH BI BJ
C as: CD CE CF CG CH CI CJ
D as: DE DF DG DH DI DJ
E as: EF EG EH EI EJ
F as: FG FH FI FJ
G as: GH GI GJ
H as: HI HJ
I as: IJ
Adding all the combinations together = 45
In other words;
=
= 45