1. In order for an object to begin to move, stop moving, or change direction, which of the following must be present?

In the image, the arrow is pointing to a celestial object. which attribute disqualifies the object from being a planet?

At very high pressures, gases become and will eventually a) more dense; become hotter b) more dense; change to a liquid or solid c) less dense; combust d) less dense; turn into a liquid

Astudent creates a model of a closed ecosystem by filling a glass tank half full with water, then adding 10 snails and two small aquatic plants. the next day, all the snails are dead. what is the most likely cause of their death?