A. Floating hollow polypropylene spheres
B. Spraying alumina powder
C. Putting cement
D. None of these
Correct Answer: Floating hollow polypropylene spheres ✔
Last Updated: February 11, 2019
A. Floating hollow polypropylene spheres
B. Spraying alumina powder
C. Putting cement
D. None of these
Correct Answer: Floating hollow polypropylene spheres ✔
Last Updated: February 11, 2019