The part of the human tooth which contains blood vessels is the

Here are the answers to the multiple-choice questions:

8. The part of the human tooth which contains blood vessels is the pulp cavity.
The correct answer is A.

9. One property of transition metals is that they have good conductivity.
The correct answer is B.

10. The main energy-providing nutrient in animal rations is carbohydrates.
The correct answer is B.

11. A common practice in crop rotation to replenish soil nutrients is alternating the types of crops planted in different years.
The correct answer is D.

12. Plants grow best in a soil that is neutral.
The correct answer is C.

13. The correct order of the last four of the first twenty elements is Chlorine, Argon, Potassium, Calcium. (Atomic numbers 17, 18, 19, 20 respectively).
The correct answer is A.

14. The most effective way to remove plaque from your teeth is by brushing and flossing.
The correct answer is A.

15. In order to complete their life cycle, mosquitoes require stagnant water.
The correct answer is C.

16. Two liquids with different boiling points can be separated using distillation.
The correct answer is A.

17. The physical differences between inner and outer planets relate to:
I. size.
II. composition.
III. density.
All three statements are correct.
The correct answer is D.

18. Pigs raised on commercial farms are often fed with a balanced diet that includes corn and soybean meal.
The correct answer is C.

19. Oxygen is not typically absorbed by plants from the soil as a nutrient; it's primarily taken from the atmosphere for respiration, though roots do require oxygen. Nitrogen, Phosphorus, and Potassium are essential mineral nutrients absorbed from the soil.
The correct answer is B.

20. In the discharging process of a capacitor, the current flowing through the resistor decreases.
The correct answer is B.

21. An element with two electrons in the core shell and three electrons in the valence shell has a total of $2 + 3 = 5$ electrons. In a neutral atom, the number of electrons equals the atomic number. So, the atomic number is 5.
The correct answer is B.

22. The element with atomic number 5 is boron.
The correct answer is D.

23. Kerosene and petrol are extracted from crude oil by fractional distillation.
The correct answer is D.