The cell membrane only lets some molecules in and out because it is
a. living
b. semi permeable
c. flexible
d. non permeable

In general in which direction does wind blow

Describe five factors that influence the value of fuel

Select the correct answer. which mutation is harmful to the organism? a. a mutation allowing moths to camouflage better on blackened tree bark b. a mutation making staphylococcus aureus resistant to the antibiotic methicillin c. a mutation inhibiting human immunodeficiency virus from attaching to and entering the cell d. a mutation causing uncontrolled cell division e. a mutation giving plant leaves a bitter taste to discourage herbivores from eating them