Answer:
1. Providing structure --> Collagen makes skin strong yet flexible.
2. Maintaining homeostasis --> Insulin controls the concentration of sugar in the blood.
3. Fighting Disease --> IgA prevents the buildup of viruses and bacteria in the gut.
4. regulating chemical reactions --> Pepsin works in the stomach to speed up the breakdown of food.
Answer:
Your gut bacteria can affect how your food is digested, how fat is stored and whether you feel hungry or full. Thus, a healthy gut bacteria may be important for maintaining a healthy weight. High-fiber foods like whole grains, fruits, vegetables, nuts and seeds can all promote healthy gut bacteria.
Explanation:
The right option is; c. biomes
Savanna is considered a transitional biome because it is intermediate between two biomes.
A savanna is a tropical grassland ecosystem that is characterized by widely spaced scattered trees. Savanna is an extensive plain that is regarded as a transitional biome because it is intermediate between moisture equator forests and tropical deserts. It covers about 20% of the earth’ surface. Savanna has seasonal water availability and during the dry season, there are strong evaporation which makes the trees such as baobab to shed their leaves while bushes and grasses wither.
It is definitely not a primary source: this would be a book itself.
Now, is it a tertiary source? I don't think so: the author of the review should have read the book and should only be referring to this book in the review.
I think it's a secondary source.