Sickle cell anemia is a genetic disorder caused by a point mutation in the hemoglobin gene of red blood cells. This mutation reduces the oxygen-carrying capacity of the red blood cells. However, this mutation in the hemoglobin gene also protects the affected individual from malaria. Which of the following best describes this mutation? A. neither harmful nor beneficial B. harmful only C. beneficial only D. both harmful and beneficial
D. both harmful and beneficial
This mutation is harmful as it causes sickle cell anemia, a condition that can lead to various health complications. However, it is also beneficial in regions where malaria is prevalent, as individuals with the mutation are more resistant to the disease.
A genetic mutation results in a mouse having whiskers that are slightly darker in color than normal. If the mutation does not impact the survival or reproduction of the mouse, which of the following best describes the mutation? A. ancestral B. neutral C. harmful D. beneficial
B. neutral
Since the mutation does not impact the survival or reproduction of the mouse and only results in a minor change in the color of its whiskers, it can be considered a neutral mutation.
Sexual reproduction involves an organism A. generating an identical offspring on the surface of its own body. B. being produced through a unique combination of DNA from two gametes. C. replicating its DNA before dividing in half to produce two organisms. D. growing from body parts that are cut or broken off the parent.
B. being produced through a unique combination of DNA from two gametes.
Sexual reproduction involves the fusion of two gametes (sperm and egg) to create a unique offspring with a combination of genetic material from both parents.
A metal block is sliding along an infinite, frictionless, horizontal plane. There are only two forces acting on the metal block: gravity and an upward force from the plane. Which of the following best describes the metal block's motion? A. The metal block will eventually slow down and stop. B. The metal block will move at the same speed forever. C. The upward force will accelerate the metal block forward. D. Gravity will accelerate the metal block downward.
B. The metal block will move at the same speed forever.
Since there is no friction to slow down the metal block, and only two opposing forces in equilibrium (gravity pulling down and the upward force from the horizontal plane), the metal block will continue to move at a constant speed forever in a straight line.
The picture below shows a solar eclipse as seen from Earth. How must the Sun, Earth, and Moon be positioned to produce the solar eclipse? A. The Sun, Earth, and Moon must be aligned in a triangle formation. B. The Sun must be between the Earth and the Moon. C. The Earth must be between the Sun and the Moon. D. The Moon must be between the Earth and the Sun.
B. The Sun must be between the Earth and the Moon.
In a solar eclipse, the Moon comes between the Sun and the Earth, blocking the sunlight and casting a shadow on the Earth.