The nucleolus is a round body found in the nucleus of most cells. although it is not technically an organelle, since it is not bound by a membrane, it can still be seen using an electron microscope and plays an important role a. regulating substances that enter and exit the nucleus. b. synthesizing ribosomes and ribosomal rna. c. synthesizing mitochondria and mitochondrial dna. d. producing the fluid in the nucleus of cells.

Which is not a characteristic of bacteria? a. they are unicellular. b. they are prokaryotic. c. they are the smallest form of life on earth. d. they are multicellular.

Which of the following factors would not contribute to allopatric speciation? a) a population becomes geographically isolated from the parent population. b) the separated population is small, and genetic drift occurs. c) the isolated population is exposed to different selection pressures than the ancestral population. d) different mutations begin to distinguish the gene pools of the separated populations. e) gene flow between the two populations is extensive.

Imagine a person stepping on a pin and pulling his or her foot away. look at the reflex arc of this scenario below. which statement best describes the image? a)the sensory nerve carries the signal from the effector to the interneuron, and the motor neuron carries the signal to the receptor. b)the motor nerve carries the signal from the receptor to the interneuron, and the sensory neuron carries the signal to the effector. c)the sensory nerve carries the signal from the receptor to the interneuron, and the motor neuron carries the signal to the effector. d)the sensory nerve carries the signal from the receptor to the motor neuron, and the interneuron carries the signal to the effector.