Along with the brown bear, it is one of only two of the eight modern bear species not considered globally threatened with extinction by the IUCN. American black bears often mark trees using their teeth and claws as a form of communication with other bears, a behavior common to many species of bears.
Planetary nebulae are astronomical objects made up primarily of gaseous materials. They are extended in size and fuzzy in appearance, and generally show some degree of symmetry. The nebula is illuminated by a central star, which sometimes is too faint to be seen.
PLANETARY NEBULAplanetary nebulae, have nothign to do with planets, instead, they are the gas remnants thrown out by some stars near the end of thier lifespan, our own sun will probably produce a planetary nebula in about 5 000 000 000 years from now planetary nebulae do NOT produce stars.