Why can oxygen diffuse across a cell membrane but a protein cannot

What is the first step in a life cycle of a plant reproduce sexually

If a set of instructions that determines all of the charactersitics of an organism is comparedto a book,and a chromosme is compared to chaper in the book,then what might be compared to a paragraph in the book?

Football players often sustain lateral blows to the extended knee. which of the ligaments is (are) damaged as a result? a. suprapatellar b. oblique popliteal and extracapsular ligament c. medial collateral, medial meniscus, and anterior cruciate d. arcuate popliteal and the posterior cruciate