Which of the following is an observation? a. the cat's claws make it harder for it to run. b. that dog must eat well because it is fast. c. the cat must have been tired from playing earlier in the day. d. the dog caught up with the cat.

The answer is D, you are observing (watching) the dog catch up with the cat. Watching the dog catch up with the cat is something you can watch/see that is why it is an observation! Hope this helped you out :)

the element that provides strength to the exoskeletons of clams and oysters is phosphorus. this is so because calcium carbonate is the main component in the shells.

explanation:

ionic bonds are two oppositely charged ions that attract. a sodium ion has a 1 positive charge; a chloride ion has a 1 negative charge. sodium and chloride have oppostive charged ions that attract which forms an ionic bond. a chemical bond formed when two atoms share electrons is called