Before there was any life on earth, which gas was absent from the ancient atmosatmosphere?

1) oxygen

2) ammonia

3) nitrogen

4) methane

The breakdown of rocks due to wind is an example of mechanical weathering chemical weathering erosion molecular weathering

A population of giraffes on a square kilometer of the African savannah contains sixteen individuals. Generally, the giraffes stay in smaller groups, surrounding scattered watering holes, where there is abundant vegetation.

At which position on an electrocardiogram do the atria contract? P wave QRS wave T wave QT interval

True or false? Plasma starts out as stem cells?

Condensed DNA is called

How is plasma constructed in blood?

Which of the following is descriptive of pertussis? a. Initial stage resembling the common old b. Prolonged illness, sometimes symptoms may last for months. c. Bacterial disease treated with erythromycin c. All of these are descriptive of pertussis

Which statement about the cell membrane is true? A. It contains cellulose and sugars that are involved in communication. B. It is present in animal cells only. C. It is rigid and elastic for supporting the cell's shape. D.

Hailey needs to identify internal costs so she can price her product accordingly. Which cost will be part of Hailey's calculation? A. cost of endangering species B. cost of deforestation C. cost of air pollution D. cost of disposing by-products E.

What is the main difference between prokaryotic and most eukaryotes cells? A. Eukaryotic cells from multi-cell tissues, Prokaryotic cells are single cell. B. Eukaryotic cells from single cell, Prokaryotic cells are multi-cell tissues. C.