Why has two different alleles for the same trait?

Why are plants called producers?

Fraction mixed number58/9

Give an example of an introduced species. How has it damaged ecosystems?

Describe one role of the trees in the oxygen cycle.

Which of followings are true? a. Most people accept that the characteristics within a population--say pesticide resistance in lice--can change over time. b.

For what percentage of time has life existed on earth round to the nearest whole number

What does this similarity at the molecular level in yeast and humans most likely indicate

Which of these activities is not considered to be a marine ecosystem threat? overfishing. ocean pollution. coastal development. ocean alkalinity?

What is another common intramuscular injection site for 2mL or less of a drug? a Ventrogluteal b. Vastus Lateralis c Deltoid d Infraspinatus

Which element acts as a hydrogen acceptor during aerobic respiration? (A) hydrogen (B) carbon (C) oxygen (D) nitrogen (E) phosphorus Can someone explain this one for me?