Which statement about the cell membrane is true?

1-it contains cellulose and sugars that are involved in communication.

2-it is present in animal cells only.

3-it is rigid and elastic for supporting the cell’s shape.

4-it prevents harmful substances from entering a cell.

How do you transfer mrna into codons ? i'm so confused : (

Drag the correct tiles to the image. not all tiles will be used. the diagram is a schematic representation of the electron transport mechanism in mitochondria. label the diagram to complete the model.

Select the situation bellow that would produce a total displacement of zero. a. a trip to the moon and then to mars b. a horse galloping from one end of a field to another c. the criss-crossing path of a bug as it flies from flower to flower d.a round-trip ride to school and back