The list below shows some events which took place at different periods in the geologic time scale.

1. sharks appear.
2. insects appear.
3. fishes with jaws appear.

which of these best orders the events from the earliest to the most recent?

1) 3, 1, 2
2) 3, 2, 1
3) 1, 2, 3
4) 1, 3, 2

Environmental differences within ecosystems are generally caused by

Which of the following would be a body response when stepping outside without a coat on a snowy day? a. senaceous glands. secrete more senum b. more liquid is transported by the body to the skin fir insulation c. blood vessels in the skin narrow and contract d. blood vessels in the skin expand

20 points and brainlist 1. london has suffered from terrible air pollution for at least seven centuries. why is the city so prone to its famous “london fog? ” what did london do to get rid of its air pollution? 2. why does air pollution cause problems in developing nations more than in developed ones?