A volcanic eruption destroyed a forest, covering the soil with volcanic ash. For many years, only small plants could grow. Slowly, soil formed in which shrubs and trees could grow. These changes are an example of Select one: a. equilibrium
b. evolution of a species
c. manipulation of genetics d. ecological succession​

d. ecological succession

Explanation:

Ecology Succession may be initiated either by formation of new, unoccupied habitat, such as from a lava flow or a severe landslide, or by some form of disturbance of a community, such as from a fire, severe windthrow, or logging.

Reference:

Wikipedia contributors. "Ecological succession." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 10 Mar. 2021. Web. 23 Mar. 2021.

A 50-year-old man is having routine blood work done as part of his yearly physical. The doctor informs him that his good cholesterol is low.  The doctor is referring to HDL cholesterol levels.

Explanation:

The doctor here is referring to HDL. HDL is good cholesterol. If the HDL level is high than it is high but on the other hand if HDL levels are low then it is risky. The Low level may arise due to bad weight, Unhealthy routine or smoking habits, Diabetes.

Low HDL levels increase the risk of heart disease. The best way to increase this good cholesterol level is to do exercise regularly and eat very healthy food.