Calcium has an atomic number of 20; therefore, calcium has 20

protons

protons plus neutrons

shells

Unlike T lymphocytes, B lymphocytes A. are made in the red bone marrow. B. recognize infected body cells. C. discover antigens in body fluids. D. are white blood cells

In this backyard garden, many groups of living things live together. Some examples include a group of bees in a hive, a school of fish in the pond, the pink chrysanthemums, and monarch butterflies hovering the flowers.

Tapeworms can't reproduce by A. budding B. fission C. fragmentation

Which sentence best explains the relationship between human population growth and the need for fracking? A. The population has decreased as demand for energy resources has increased B.

Is the plant oleander vascular or non vascular

Which sources do scientists use to reconstruct past climate conditions? Check all that apply. fossils frozen in glaciers daily temperatures pollen grains preserved in sediment running water tree rings

In beetles, the gene for color and the gene for pattern are located on the same chromosome and exhibit recombination.

Nucleic acids are composed of monomers called?

Cyclic amp (camp) stimulates one's metabolic rate. many supplement companies offer products claiming to increase the levels of this chemical within the body.

Injecting a person with a killed-bacteria vaccine can protect that individual from a disease because the proteins of the bacteria: A) remain in the body and live bacteria later prey on them instead of live tissue B) blind with receptors in the body,