What percent of the world's species were wiped out in the most recent mass extinction, 65 million years ago? A. 100% B. 50% C. 25% D. 75%

It is difficult to observe individual chromosomes with a light microscope during interphase because __ 1) the DNA has not been replicated yet 2) they have uncoiled to form long, thin strands 3) sister chromatids do not pair up until division starts 4) the spindle must move them to the metaphase plate before they become visible 5) they leave the nucleus and are dispersed to other parts of the cell

Which of the following types of cells is most responsible for responding to color? Rods Ganglion cells Bipolar cells Cones Optic nerve

The central sulcus separates which two lobes of the brain? a) Frontal and occipital b) Temporal and parietal c) Occipital and insular d) Frontal and parietal

What is the ultimate source of all diversity? 1) natural selection 2) sexual recombination 3) meiosis 4) mutation

Mad cow disease is caused by __ 1) a retrovirus similar to HIV 2) an enveloped virus 3) infectious proteins called prions 4) viroids

Gastrin is a digestive hormone that is responsible for the stimulation of acid secretions in the stomach. These secretions are stimulated by the presence of: A) protein and peptide fragments. B) starches and complex carbohydrates. C) simple carbohydrates and alcohols. D) fatty acids.

A protein produced in the body that recognizes another molecule as "foreign" to the body is a(n) __ 1) lymphocyte 2) antibody 3) antigen 4) phagocyte 5) platelet

The enzyme that adds nucleotides to form new strands of DNA is 1) amylase. 2) transcriptase. 3) ligase. 4) helicase. 5) DNA polymerase.

Which event occurs during anaphase? 1) Sister chromatids become separate chromosomes. 2) Chromosomes line up in the middle of the cell. 3) The nuclear envelope breaks up. 4) The mitotic spindle begins to form.

During metaphase, __ 1) the nuclear envelope breaks up 2) sister chromatids move near the poles 3) centrosomes divide 4) chromosomes line up in the middle of the cell