Ed invented a device used in gasoline pumps to control gas fumes. which of the following would protect him from others copying his devise?

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

Scientific models are based on current knowledge, which can limit their effectiveness when new discoveries are made.

Awhite-blue star is hotter than a red star. select the best answer from the choices provided true or false