Answer:
Guessing you just need help with the definition but if it's the question I can still help you.
A and B are equivalent. That's one way instruments are often grouped. (the "sopranos", the "altos", the "bass")
C is another way instruments are often grouped; (the "woods", the "brass")
D is another way instruments are often grouped; (the "strings", the "percussions")
Answer:
0 Kelvin
Explanation:
Atoms in absolute temperature get approximatelly motionless since 0 Kelvin is -273 degrees Celcius. The kinetic energy of atoms/particles in matter has the possible lowest value ( almost zero), so that there is nothing colder than 0 Kelvin.
Before 7 after 9. A pH smaller than 7 indicates acidity with 0 being completely acidic. A pH greater than 7 shows alkalinity with 14 being completely alkaline. 7 is neutral. Since NaOH is alkaline, adding it to a neutral substance would increase the pH and it would increase from 7 to 9.
