What are stem cells and where do they come from?

The iris in the human eye contracts and expands, controlling the amount of light that reaches the retina. What types of muscle control this?

What is a negative outcome of extinction? What is a positive outcome of extinction?

How is carbon reintroduced into the atmosphere? a. respiration b. photosynthesis c. evaporation d. all of the above

How is population size affected by limiting factors?

Due to the risk of reye's syndrome, children with fever should not be given medications containing which substance? g

How are nerve cells adapted to carry electrical messages?

If B is dominant for brown eyes and b is recessive for blue eyes, write the genotype and phenotype shown for #1-3. 1. Homozygous dominant 2. Homozygous recessive 3 Heterozygous

Photosynthesis removes A: oxygen from the atmosphere and puts it in food B: sunlight from the earth C: carbon from the atmosphere and puts it in food D: pollution from the atmosphere

For an object to remain at rest, which of the following must be true?

A particular plant has two alleles that control the length of its stem. T represents the dominant allele that codes for a tall stem, and t represents the recessive allele that codes for a short stem.