Which statement is true about the part of the electromagnetic spectrum that is divided into seven ranges of wavelengths?

a. it is one of three parts visible to the human eye.
b. it is the only part visible to the human eye.
c. it is one of two parts visible to the human eye.
d. it cannot be seen by the human eye unless it rains.

In which situation has the independent variable for the experiment been changed? check all that apply. changed from counting the number of duckweed at day 0 and day 14 to counting them every day changed from testing duckweed growth in beakers to testing duckweed growth in large outdoor tanks changed from testing the effect of ph on duckweed growth to testing the effect of light levels on duckweed growth changed from testing the effect of acid ph on duckweed growth to testing the effect of basic ph on duckweed growth

Ammonia enters the expansion valve of a refrigeration system at a pressure of 10 bar and a temperature of 18oc and exits at 6.0 bar. the refrigerant undergoes a throttling process. determine the temperature, in oc, and the quality of the refrigerant at the exit of the expansion valve.

Which type of basaltic lava flow has a fairly smooth