Trilobites were abundant in pennsylvania. trilobites were among the first of the arthropods, a phylum of hard-shelled creatures with multiple body segments and jointed legs. their fossils first appeared in early cambrian period about 570 million years ago. the trilobite fossils show that during most of this time pennsylvania was providing favorable conditions for the trilobites.
a) glacial terrain
b) a dry and sandy plain
c) mostly mountain ranges
d) covered by warm, shallow seas

Indicate the coat color and the proportion of offspring with that color for each of the following crosses of rabbits. assume all are homozygous. albino x albino a) 1/4 chinchilla, 3/4, agouti b) 3/4 albino, 1/4 chinchilla c) all albino

You have just sequenced a new protein found in mice and observe that sulfur-containing cysteine residues occur at regular intervals. what is the significance of this finding? it will be important to include cysteine in the diet of the mice. cysteine residues are required for the formation of α helices and β pleated sheets. cysteine residues are involved in disulfide bridges that form tertiary structure. cysteine causes bends, or angles, to occur in the tertiary structure of proteins.

Suppose you use three different scale to weigh a bag of oranges. one scale says the nag weighs 2.1 lb, and third says it weighs 2.1 lb. the actual weight of the bag of oranges is 2.153 lb. which of the following best decribes these results?