People with type o blood can be universal donors because their red blood cells do not contain either a antigen or b antigen on their surface.

2. in dragons, a gene on chromosome 1 codes for wing color and a gene on chromosome 2 codes for body color. draw out the stages of meiosis for these two chromosomes from a dragon that is heterozygous for both traits. define your alleles. what are all the possible allele combinations of the gametes produced?

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.

When analyzing tree rings, what do scientists assume a thin ring indicates?