Science Test #7 Flashcards

A scientist observes that a population of bacteria doubles every 20 minutes under ideal conditions. What type of growth pattern does this represent?

Answer: Exponential growth

Exponential growth occurs when a population multiplies by a constant factor over equal time intervals, such as doubling every 20 minutes.

Which of the following best explains why ice floats on liquid water?

Answer: Ice is less dense than liquid water due to hydrogen bonding

Water molecules in ice form a crystalline lattice held together by hydrogen bonds, creating a less dense structure than liquid water.

During photosynthesis, what happens to carbon dioxide molecules?

Answer: They are converted into glucose using light energy

In photosynthesis, plants use light energy to convert carbon dioxide and water into glucose and oxygen.

A car traveling at 60 mph applies its brakes and stops after 4 seconds. What physical concept explains the car's resistance to stopping?

Answer: Inertia

Inertia is the tendency of an object in motion to remain in motion, which causes the car to resist the change in its state of motion.

Which layer of the Earth is responsible for generating Earth's magnetic field?

Answer: The outer core

Earth's magnetic field is generated by the movement of molten iron and nickel in the liquid outer core.

A student notices that plants in a shaded area have larger, thinner leaves than plants of the same species in full sunlight. This is an example of:

Answer: Phenotypic plasticity

Phenotypic plasticity is the ability of an organism to change its physical characteristics in response to environmental conditions without changing its genes.

What is the main difference between a physical change and a chemical change?

Answer: Chemical changes produce new substances; physical changes do not

A chemical change results in the formation of one or more new substances with different properties, while a physical change alters only the form or appearance of a substance.