Question

question 5 (1 point)
the eyes and the respiratory tract are both protected against infections by
-------------.
○ the release of slightly alkaline secretions
○ the secretion of lysozyme onto their surfaces
○ the secretion of complement proteins
○ interferons produced by immune cells
question 6 (1 point)
oxygen crosses a plasma membrane
○ through simple diffusion
○ with the help of nonspecific transporter
○ by osmosis
○ through facilitated diffusion

Explanation:

Question 5

To determine the correct answer, we analyze each option:

• Option 1: Eyes and respiratory tract don't rely on slightly alkaline secretions for protection.
• Option 2: Lysozyme is an enzyme that breaks down bacterial cell walls. Tears (for eyes) and mucus in the respiratory tract secrete lysozyme, protecting against infections. This matches.
• Option 3: Complement proteins are part of the immune system but act in the bloodstream, not on the surfaces of eyes/respiratory tract.
• Option 4: Interferons are involved in viral defense, not a primary protection for eyes/respiratory tract surfaces.

To determine how oxygen crosses a plasma membrane:

• Option 1: Simple diffusion is the movement of small, non - polar molecules (like O₂) from high to low concentration, without energy or a transporter. Oxygen is non - polar and small, so it uses simple diffusion.
• Option 2: Oxygen doesn't need a nonspecific transporter.
• Option 3: Osmosis is for water movement across a semi - permeable membrane, not for oxygen.
• Option 4: Facilitated diffusion requires a transporter, which oxygen doesn't need.

Answer:

B. the secretion of lysozyme onto their surfaces

Question 6