the cell membrane is selectively permeable. o2 diffuses across the phospholipid bilayer. k+ must cross the cell membrane using a membrane protein. which property of the cell membrane prevents the diffusion of k+?

a) the membrane proteins are attracted to the charged ions.

b) only very small particles are able to diffuse across the cell membrane.

c) the lipid tails are hydrophobic, repelling charged ions such as k+.

d) the phosphate heads are hydrophobic and prevent the passage of polar substances.

80 points pls brainliest 1. what does a red shift mean? blue shift? 2. describe the big bang theory. according to this theory, how old is the universe? 3. scientists believe the universe is expanding. what is the evidence that supports this? 4. describe a nebula. 5. describe the 3 types of galaxies. what is a barred spiral galaxy? 6. what is a light year? how far is alpha centauri from earth? 7. describe the universal law of gravitation. be sure to include gravitational force between two objects. 8. describe the planets’ orbits around the sun. 9. what is the asteroid belt? where is it located? 10. describe rotation and revolution of earth. what determines an earth day and year? 11. how do galaxies exist? 12. compare and contrast the inner and outer planets. 13. what causes the seasons?