Why is it important for an organism to have the correct number of chromosomes

How do scientists organize the major events of Earth's history?

How well do the continents fit together

Secretory proteins are A. produced by ribosomes on the smooth endoplasmic reticulum B. chemically modified in the nucleus C. produced by the cell for internal use D. released from the cell through the plasma membrane E.

Protective layer that covers a leaf

One celery stick is placed in a beaker of pure (100%) water. A different celery stick is placed in a beaker of an 80% water and 20% solute solution. Predict the outcome.

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.

List (A) the primary materials necessary for and (B) The materials produced by photosynthesis