How is an electromagnet different from a permanent magnet?

a. it has only north magnetic poles.
b. it has only south magnetic poles.
c. there is no magnetic field.
d. it can be turned on and off.

Invasive species are one of the major threats to biodiversity. these species multiply quickly and compete with native species for food, sunlight, spac and other resources. on the map, determine the area where native species will have limited resources available to them due to invasion threat from invasive species threat very low low medium high very high

Explain how organisms could be harmed by high levels of salt from roadways?

The body of water found at number 4 on the map above is the