They are both are types of explanations.
A membrane that allows only some materials to move in and out of the cell is B. Semipermeable.
Answer:
A phospholipid
a. has both polar and nonpolar regions.
Explanation:
Phospholipids, as amphipathic molecules, consist of a glycerol molecule, two fatty acids, and a phosphate group that is modified by an alcohol. The phosphate group is the negatively-charged hydrophilic (water-loving) polar head, which face outward and are attracted to the intracellular and extracellular fluid. The fatty acids are the uncharged, hydrophobic (water-fearing) nonpolar tails, which face the inside, away from the water and meet in the inner region of the membrane.
Answer: I'll help
Explanation:
21. Wood
22. 1885
23. 1890
24. 1945
These are rough estimates because it's a little difficult to interpret the graph but this should be close enough hopefully
