Free Bachelor of Science: Intro to Life Sciences Questions and Answers — Questions and Answers
Question 1: What components of the following central nervous system are they?
- Brain and kidneys
- Brain and spinal cord (Correct answer)
- Spinal cord and kidneys
- Spinal cord and muscles
Correct answer: Brain and spinal cord
The central nervous system (CNS) is the main control center of the body, responsible for processing information and coordinating responses. It is primarily composed of two major components: the brain and the spinal cord. These two structures work together to integrate sensory information, generate motor commands, and regulate various bodily functions.
Question 2: The ____ system consists of the liver and kidneys.
- Muscular
- Vascular
- Excretory (Correct answer)
- Skeletal
Correct answer: Excretory
The excretory system is responsible for filtering waste products from the blood and expelling them from the body. Key organs involved in this vital process include the kidneys, which filter blood to produce urine, and the liver, which processes toxins and produces bile to aid in waste removal. Together, these organs ensure the body's internal environment remains clean and balanced.
Question 3: The digestive system includes the small intestines. The location of ____ is here.
- Production of toxins
- Toxin exchange
- Oxygen exchange
- Nutrient absorption (Correct answer)
Correct answer: Nutrient absorption
The small intestine is a crucial organ in the digestive system, primarily responsible for the absorption of nutrients from digested food. Its inner surface is highly specialized with villi and microvilli, which significantly increase the surface area available for efficient uptake of carbohydrates, fats, proteins, vitamins, and minerals into the bloodstream. While digestion begins earlier, the vast majority of nutrient absorption occurs here.
Question 4: The tissue that ____ is the placenta.
- fertilizes the egg
- supplies nutrients to a developing embryo (Correct answer)
- produces female gametes
- produces male gametes
Correct answer: supplies nutrients to a developing embryo
The placenta is a temporary organ that develops in the uterus during pregnancy, forming a vital connection between the mother and the developing fetus. Its primary function is to facilitate the exchange of essential nutrients, oxygen, and waste products between the maternal and fetal bloodstreams. This ensures the embryo receives everything it needs for healthy growth and development.
Question 5: Describe the zygote.
- An immature sperm cell
- A fertilized ovum (Correct answer)
- An immature ovum
- The place where female gametes are produced
Correct answer: A fertilized ovum
A zygote is the initial diploid cell formed when two haploid gamete cells, typically an egg (ovum) and a sperm, fuse during the process of fertilization. This single cell contains the complete genetic material from both parents and represents the very first stage of embryonic development. The zygote then undergoes rapid cell division to form an embryo.
Question 6: Which of the following methods of natural selection makes use of the claim that newborns with medium weights often fare better than those who are especially little or large?
- Median selection.
- Disruptive selection.
- Stabilizing selection. (Correct answer)
- Typical selection.
Correct answer: Stabilizing selection.
Stabilizing selection is a type of natural selection where genetic diversity decreases as the population stabilizes on a particular non-extreme trait value. In this scenario, newborns with medium weights have a higher survival rate compared to those who are either very small or very large. This selective pressure favors the average phenotype, leading to a reduction in variation around the mean.
Question 7: Which of the following examples of natural selection is NOT one?
- Disruptive selection.
- Directional selection.
- Stabilizing selection
- Heterozygote selection (Correct answer)
Correct answer: Heterozygote selection
Disruptive, directional, and stabilizing selection are the three main modes or types of natural selection, describing how phenotypes are favored or disfavored in a population. Heterozygote selection, while a significant evolutionary concept often leading to heterozygote advantage, describes a specific condition where heterozygous individuals have higher fitness. It is not classified as a fundamental *mode* of natural selection in the same way as the other three.
Free Bachelor of Science: Intro to Life Sciences Questions and Answers
What components of the following central nervous system are they?