What term describes the thick, sticky substance obtained from resinous trees used in embalming?

The term that describes the thick, sticky substance obtained from resinous trees used in embalming is "balsamic substance." Balsamic substances, derived from the resin of various trees, have been traditionally used in embalming practices due to their preservative qualities and aromatic properties. These substances help in the preservation of the body and mask odor, making them particularly valuable in the embalming process.

Linseed oil, while used in various applications including wood finishing and oil paints, does not have the properties advantageous for embalming. Pine tar also has distinct uses, particularly in preserving wood and in medicinal applications, but it's not specifically associated with the embalming process in the same way as balsamic substances. Elemi gum, which comes from certain species of trees, has its uses but is less commonly mentioned in the context of embalming compared to balsamic substances.

The specific properties and historical use of balsamic substances in embalming make it the correct answer in this context.