The organisms that produced the oxygen gas in Earth's early atmosphere were

What arguments would you use to justify calling the mitochondria the "powerhouse" of the cell?

List two human activities and two natural events that can cause a large increase in the rate of soil erosion

Photosynthesis and cellular respiration are ___ ___ that occur in cells. chemical reactions physical reactions

Which of the following does not represent a property of water? a. a frozen lake b. a mosquito standing on water's surface c. a glass of sweetened tea d. all of the above e. none of the above

Which common sexually transmitted disease is caused by the bacterium chlamydia trachomatis? a. chlamydia b. pruritus vulvae c. trichomoniasis d. gonorrhe?

A new, sixth global mass-extinction event appears to be occurring on earth today. the most likely explanation for the dramatic loss of species is

What must happen to pyruvate before it can enter the kreb's cycle? explain.

Select all that apply. Over time plants and animals have developed defenses against being eaten. What are some examples of these defense mechanisms?

If you were an electron, and your home town was your nucleus, what would you need to do in relation to your home town to emit light (release energy) ?

Which of these provides the best evidence of the environment in which an igneous rock was formed?