The correct answer to my knowledge 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
Once you add all the combinations together, you get 45.
Hoping this helped you!
Yes they can because the catalyst does not take part in the chemical reaction and remains unchanged after the reaction has ended. Biological catalysts are known to be recycled by the bodies in which they work.
The correct option is C.
When a dog is afraid, its ears are usually pinned back to the head. A dog showing aggression will pulled its ear up and forward.
Other signs that a dog shows when it is afraid include: lowering of the head, wrinkling of the nose, curled lips that show many teeth, tucked tail, panting, etc.
Signs show by an aggressive dog include: head held high, curled lips only show the front teeth, tail is upright and stiff, no panting, etc.
