13. What causes a heartbeat?………… A. Stretching of the atrium and ventricle muscles
B. Closing and opening of AV and SV Valves
C. Oxygenated blood
per minute
D. The number of times your heart beats

Why reason best illustrates why hershey and chase chose to use viruses in their experiment?

Which statement correctly describes a way that mutations increase the likelihood that a species will survive in a changing environment

Which set of characteristics best describes sedimentary rock? a) largest type of rock, made of organic matter, hardest type of rock b) often contains layers, forms near sources of water, contains fossils c) least abundant type of rock, made of other rocks, made mostly of minerals d) most abundant type in earth's crust, made of magma/lava, contains no fossils