Surfactant:
a) is produced by pneumocytes type i.
b) phagocytizes dust or debris.
c) replaces mucus in the alveoli.
d) plays a key role in keeping alveoli open.
e) is not found in healthy lung tissue.

The correct answer will be option-D

Explanation:

Pulmonary Surfactant is a complex substance produced by the pneumocytes epithelial II cells in the alveolar sac.

The surfactant is composed of the proteins and lipids which plays a role in keeping alveoli open by reducing the surface tension formed between the air and liquid.

The surfactant act by forming a monolayer surface film which helps reduce the surface tension.

Thus, option-D is the correct answer.

the transfer of energy between two molecules spaced just nanometers apart plays a key role in many technologies, including photovoltaics, quantum information systems, lighting, and sensors, as well as in biophysics to measure nanometer distances and in photosynthesis. but an open question in this area is what effect, if any, the surrounding photonic environment has on this nanoscale energy transfer. by designing and performing a carefully controlled experiment to answer this question, scientists have settled the debate and found clues to improving the efficiency of many of the technologies that rely on this process.

explanation:

1. dermis

2. chemical

3. urine

4. viruses

5. antibodies