Which statement about a flat magnet that can stick onto a refrigerator is true

Ineed extreme for task 2. my student number is 571721. many to whoever solves this correctly, im in debt to you.

What color of light must blue light mix with to create white light? a. yellow b. white c. blue d. green

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