Here's a hypothesis for the duckweed experiment: "if duckweed is grown at pH 5, then it will grow at the same rate as when grown at pH 7, or normal pH, because it can tolerate mildly acidic environments." Which elements should be controlled variables for this experiment?

Check all that apply.

- environmental pH

- ✓ timing of experiment

- duckweed population

- ✓ environmental light

- ✓ amount of nutrients

- ✓ environmental temperature

the answers for whoever needs it :)

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The optimistic view of human nature held by supporters of the humanistic perspective led to more positive views of human nature throughout the field of psychology.t or f?

During physical science, ms. greene challenged her students to produce an energy transformation. james and jill wrapped a 4-inch nail with a coil of fifty turns of wire. they connected one end of the coil to one terminal of a knife switch. they connected the other terminal of the knife switch to the battery. finally, they connected the end of the coil to the other terminal of the battery. james held the tip of a 1-inch nail near the flat end of the 4-inch nail. jill closed the knife switch quickly and then opened it. the 1-inch nail was pulled toward the 4-inch nail. what is the best explanation of why the nail moved? a) electrical energy was converted to mechanical energy in the 1-inch nail. b) the 4-inch nail became an electromagnet and the magnetic force attracted the 1-inch nail. c) the electric current in the 4-inch nail was converted to mechanical energy in the 1-inch nail. d) the 4-inch nail had a positive charge and the 1-inch nail had a negative charge. opposites attracted.

Researchers determine that the biodiversity in a woodland region is declining. they identify two major threats to the region's biodiversity, a method to address each threat, and the expected outcome of each method. this information is shown in the table. a) reforestation would not benefit many species because most forest species live on the ground. b) reforestation would take the longest time to be effective because trees take several years to grow. c) biological augmentation would benefit only a few species because is is typically not very effective. d) biological augmentation would take less time to ve effective because it targets the majority of prey species.