20. How was randomization used in this experiment?
Answer choices:
The individuals were randomly
selected to participate.
The temperature, bedding, and
lighting were the same for all.
The colored chips were used to
determine the treatments.
The days they were asked to
sleep at the clinic were random.

D. The days they were asked to sleep at the clinic were random. Hope it helps!~

(Sorry if you get it wrong or I got it wrong-)

~The Confuzzeled homan

b

step-by-step explanation:

x + y = 90 5x – 10y = 90 90 – 10y = 5x 90 + 10y = 5x

step-by-step explanation:

last month maria hiked the 5-mile mountain trail a number of times and she hiked the 10-mile canal trail several times. let x represent the number of times she hiked the 5-mile trail, and let y represent the number of times she hiked the 10-mile trail. if she hiked a total of 90 miles, which equation can be used to find the number of times maria hiked each trail? x + y = 90 5x – 10y = 90 90 – 10y = 5x 90 + 10y = 5x