T/f early english explorers encountered conflict and native american resistance when they tried to establish jamestown.

1 - wave length

2 - amplitude

3 - crest

4 - trough

explanation:

duh.

adding a(n) to an electric circuit would increase the magnetic field around a wire;

b. solenoid

a solenoid is a type of electromagnet whose purpose is to generate a controlled magnetic field.

if the purpose of the solenoid is instead to impede changes in the electric current, a solenoid can be more specifically classified as an inductor rather than an electromagnet.