What is bone marrow? What two types of bone marrow exist, and why are they important to the overall health of the body? We think of our bones simply as hard mineral structures that give our bodies a frame. But in fact, our bones aren’t only a matrix of calcium, phosphorus, and collagen. Our bones … More Biology – Lesson 170

You learned about osmosis early on in this course. Why is osmosis essential to the function of the kidneys? Be sure to mention the nephron, loops of Henley, adrenal cortex and medulla in your essay. Osmosis is a process which is constantly occurring in our bodies. It is a process where water flows through a … More Biology – Lesson 160

When you find yourself breathing hard or gasping for breath, is this due to a lack of oxygen or an excess or carbon dioxide? Explain your answer, including a discussion of feedback systems and the mechanisms that are at work when you breathe. When the pH of the blood is low, there are high concentrations … More Biology – Lesson 150

Suppose you found the bones of an unidentified animal. How could you learn about what the animal ate? What specific structures would give you clues about the creature’s diet? If I found the whole skeleton of an animal and wanted to know what the animals diet consisted of, I would look to the animals teeth. … More Biology – Lesson 140

Why do marsupials give birth to underdeveloped young, only to nurture them in a pouch? What possible advantages does this set-up provide for a marsupial? It is still not fully clear why marsupials give birth so quickly, usually remaining pregnant for only two to four weeks. There are some possible upsides of this process though. … More Biology – Lesson 130

Can a poisonous arthropod provide benefits to human beings? Are there virtues in the venom? Give a few examples to support your point of view. Many arthropods, such as scorpions, insects, and spiders, have a reputation of being a nuisance and even potentially harmful. But even if they can be a little scary, that doesn’t … More Biology – Lesson 120

What is a chordate? How are vertebrates different from chordates? The definition of Chordate is an animal of the large phylum Chordata , comprising the vertebrates together with the sea squirts and lancelets. The definition of Vertebrate is an animal of a large group distinguished by the possession of a backbone or spinal column, including mammals, birds, reptiles, … More Biology – Lesson 110

How does water move through the body of a plant? Plot the route, in general terms, from roots to leaves. Include all the major tissues, organs, and structures involved, and their role in the movement of water. First, water is passively transported into the roots from the soil and then into the xylem. The xylem is vascular … More Biology – Lesson 100

On the path from pollination to germination, there are many things that will slow down or delay the reproduction of a plant. Describe two or more of these delaying factors, and explain how each could actually be helpful to the plant species. A plant can have many issues between pollination and germination, but today I’d … More Biology – Lesson 90

Give one or more reasons that photosynthesis is challenging for plants in a desert environment. Describe in detail the adaptations that plants have made in order to deal with this challenge. You should be thinking of biochemical issues, not merely ways that a plant conserves water. Photosynthesis is very challenging in a desert environment, because … More Biology – Lesson 80