Yannick’s class measured the width of one leaf several times. the values that the class recorded included 10 mm, 8 mm, 15 mm, 5 mm, and 13 mm. what is lacking from the measurements that the class made?

a calibration
b precision
c repetition
d validation

phylogenetic tree is the tree of life or evolution tree. it shows the different branches of evolution. the sequence goes like tissues - coelom - backbone - endoskeleton - segmentation

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds