To study the effect of workplace lighting on employee productivity, a researcher first manipulates the amount of lighting in a workspace and then observes its effect on a group's productivity. in this case, the researcher is focusing on which element of inferences of cause and effect?

Acrosswalk_when there are no pavement markings.

Bakery has bought 250 pounds of muffin dough. they want to make waffles or muffins in half-dozen packs out of it. half a dozen of muffins requires 1 lb of dough and a pack of waffles uses 3/4 lb of dough. it take bakers 6 minutes to make a half-dozen of waffles and 3 minutes to make a half-dozen of muffins. their profit will be $1.50 on each pack of waffles and $2.00 on each pack of muffins. how many of each should they make to maximize profit, if they have just 20 hours to do everything?

Melissa is a very generous single woman. before this year, she had given over $11,400,000 in taxable gifts over the years and has completely exhausted her applicable credit amount. in the current year, melissa gave her daughter riley $100,000 and promptly filed her gift tax return. melissa did not make any other gifts this year. how much gift tax must riley pay the irs because of this transaction?