1.   An undisclosed number of flight-tracking agents will be added to improve the flow of information about flights, Nowack said.

2.   In addition, chemicals are usually added to improve the consistency and performance of the oil.

3.   Our lawn was recently aerated and had gypsum added to improve the hard pan clay, and I would like to encourage better growth this summer.

4.   Unflavored gelatin frequently is added to improve texture.