Answer to Question 1
If a cloud is less dense, the starlight may be able to penetrate it, and stars can be seen through the cloud; but the stars appear dimmer because the dust in the cloud scatters some of the light. Because shorter wavelengths are scattered more easily than longer wavelengths, the redder photons are more likely to make it through the cloud, and the stars appear redder than they should for their respective spectral types. This effect is called interstellar reddening. The same physical process makes the setting Sun look red. The fact that distant stars are dimmed and reddened by intervening gas and dust is clear evidence of an interstellar medium.
Answer to Question 2
T Tauri stars are protostars with about the mass of the Sun that show signs of active chromospheres as you might expect from young rapidly rotating stars with strong magnetic dynamos. T Tauri stars are also often surrounded by thick disks of gas and dust that are very bright at infrared wavelengths.
The logistic growth model does not describe all populations.
Stars and the Interstellar Medium
Stars and the Interstellar Medium
A Connection to Interstellar Space
The Number of Children Americans Think Are Ideal
Describe the Conceptual Forecasting Framework in your own words.