Why do scientists use control groups in experiments?

The table shows dates and appearance of index fossils. which rock layers can be dated most precisely? a) a layer containing both a fossil 4 and a fossil 3 b) a layer containing both a fossil 2 and a fossil 3 c) a layer containing both a fossil 1 and a fossil 4 d) a layer containing both a fossil 1 and a fossil 2

What do all macromolecules have in common with each other? oa. they all are formed from the same elements.ob. they all have major roles in cell membranesoc. they all act as catalysts in the body.od. they all have peptide bonds between carbon atoms.

Answers to mastering biology drag the labels to their appropriate locations to complete the punnett squares for morgan's reciprocal cross. drag blue labels onto the blue targets to indicate the genotypes of the parents and offspring. drag pink labels onto the pink targets to indicate the genetic makeup of the gametes (sperm and egg). labels can be used once, more than once, or not at all. hints