State the type of integral, membrane-spanning protein that allows the facilitated transport of materials in and out of the cell.

Most animal cells membranes have proteins that pump ions out of the cell and potassium ions into the cell

Which of the following types of stars are dim but can have high surface temperatures? giants main sequence stars supergiants dwarfs

Which kind of mutation has occurred when the codon for an amino acid is changed to a stop codon? a. a silent mutation b. a missense mutation c. a frameshift mutation d. a nonsense mutation