There are many different types of scientific investigations. Which of the following forms requires the identification and control of variables?

A.

model-building

B.

observational field studies

C.

collection of specimens

D.

laboratory experiments

Which method of selection is used to choose civil servants? pols210?

Which best explains why muscle cells are different from blood cells? A. A mutation occurs during the development of muscle cells but not in blood cells. B. Different genes are activated in muscle cells than in blood cells. C.

What is the only artery in the body that carries deoxygenated blood

What causes glow sticks to have different colors?

Name two types of substances that do not contain molecules with covalent bonds

Clover will flower if exposed to 8 hours of dark and 16 hours of light. It will not flower if exposed to 16 hours of dark and 8 hours of light. However, if the 16 hours of dark is interrupted with a brief period of light the clover will flower.

This disaster results from an abnormal rise of water generated by a storm, over and above the predicted astronomical tides.

A student observes poor growth of plants in a garden containing high clay content. Clay content reduces drainage in soil. Which of these is the best method to improve plant growth in the garden?

Jelaskan bukti bahwa senyawa memiliki sifat berbeda dengan atom penyusunnya?

Why is a symptomless STI just as dangerous as an STI that exhibits symptoms? Explain your answer.