In a controlled experiment,
a. a control group is compared with one or more experimental groups.
b. there are at least two variables.
c. all factors should be different.
d. a variable is not needed.

Zoe decided to measure the hand length of each of her classmates. first she marked a line across each student's wrist and lined up a ruler from this mark to the top of the middle finger to measure the length. then she recorded the measurements in the table below. marla did this the same way for each classmate, and then zoe used this ruler to measure each straight line and record the data below. this data is invalid. what is the most likely reason why it is invalid? the ruler is marked in centimeters, but zoe recorded data in inches. the range of lengths is too wide, so zoe must have misread the ruler. marla’s complicated measuring procedure was overly confusing. marla could have been inconsistent while drawing outlines of fingers.

In what part of a chloroplast does glucose production occur? a. atp synthase b. photosystem ii c. photosystem d. stroma

Which of the following would be a body response when stepping outside without a coat on a snowy day? a. senaceous glands. secrete more senum b. more liquid is transported by the body to the skin fir insulation c. blood vessels in the skin narrow and contract d. blood vessels in the skin expand