Unit 2A Test Review: Microscopes, Clell Theory, Law vs. Theory

Which statement best describes a scientific theory?

• A scientific theory is supported by a large body of evidence and can be revised with new discoveries.

• A scientific theory is a guess made by scientists without any testing.

• A scientific theory is a fact that cannot be changed.

• A scientific theory is a personal belief held by scientists.

For many years, people believed that living things could develop from nonliving materials. This idea was called spontaneous generation. Which statement from cell theory directly contradicts the idea of spontaneous generation?

• All living things are made up of cells

• Cells are the smallest units of life

• New cells are produced only from existing cells

• Cells can exist independently of other cells

Although Robert Hooke observed cork cells in 1665, the cell theory was not fully established until the 19th century. What was a major reason for the delay in the acceptance of the cell theory?

• Scientists were unable to agree on the definition of a cell until the 20th century.

• It took many years of observing and studying a wide variety of organisms before scientists could gather enough evidence to support the cell theory.

• The technology to observe living cells did not exist until after 1900.

• The idea of cells was rejected by most scientists until it was proven by genetic experiments.

Which of the following best illustrates how a scientific theory is developed and refined?

• Maria conducts a single experiment and immediately publishes her explanation, which she never changes regardless of new evidence.

• Jamal observes a rare event once and writes a detailed explanation, but no one else has been able to observe or repeat the event.

• Scientists from different research groups repeatedly test similar hypotheses, share their results, and update their explanation as new data becomes available.

• Elena forms an explanation after one experiment and refuses to consider other scientists' findings that contradict her results.

Tags

NGSS.HS-PS1-2

Which of the following best describes a statement that summarizes a pattern found in nature without providing an explanation?

• Scientific law

• Scientific theory

• Scientific hypothesis

• Scientific experiment

Which of the following best distinguishes a scientific theory from a scientific law?

• A theory explains why natural phenomena occur, while a law describes what happens under certain conditions.

• A law is a complex explanation, while a theory is a simple statement of fact.

• Theories are never revised, but laws are frequently changed.

• Laws are supported by less evidence than theories.

Microscopes can be used to explore cells. Which of the following types of microscopes is used to produce a three-dimensional image of the surface of a cell?

• simple light microscope

• compound light microscope

• scanning electron microscope

• transmission electron microscope

Which of the following items would be best examined under a dissecting microscope?

• A stained collection of cheek cells

• A thin sample of a protein molecule

• A seashell collected at the beach

• A DNA molecule

In a controlled experiment, scientists investigated how temperature affects the growth of the wood frog. After 7 days, the wood frogs in group 3 did not survive. The explanation reached by some of the researchers was that the wood frogs in group 3 were unhealthy before the experiment started. What is the best alternative explanation for what happened to the frogs in Group 3?

• Group 3 was fed a different diet.

• Group 3 cannot grow in captivity

• Group 3 had a tank that was too hot.

• Group 3 was outcompeted by Group 1 and Group 2.

Tags

NGSS.MS-LS1-5

NGSS.MS-LS2-4

Scientific methods involve careful observation, forming hypotheses, conducting experiments, and analyzing data to reach conclusions that can be tested and verified by others. In contrast, pseudoscientific claims often rely on anecdotal evidence, lack reproducibility, and are not open to critical scrutiny or peer review. Distinguishing between science and pseudoscience is important for making informed decisions based on reliable knowledge. Which one is considered to be science

• Numerology: assigns mystical significance to numbers and their influence on human life, but it is not supported by scientific research or objective evidence.

• Phrenology: suggests that personality traits can be determined by the shape of the skull, yet it lacks empirical support and scientific credibility.

• Crystal Healing: claims that crystals have healing powers, but these claims are not backed by controlled scientific studies or reproducible results.

• The Germ Theory of Disease: states that microorganisms cause many diseases, a concept supported by extensive laboratory research and medical evidence.

Tags

NGSS.HS-PS4-3