Question

question 1
which of these statements best summarizes the cell theory?

• cells are the building blocks of living things.
• cells contain a nucleus and other parts.
• cells can be seen through a microscope.
• cells come in different shapes and sizes.

question 2
scientists developed a better understanding of single-celled organisms after the development of which tool?

• the mercury thermometer
• the triple beam balance
• the petri dish
• the microscope

Explanation:

Analyze Question 1

Using the Cell Theory knowledge point

• Cell theory states that all living organisms are composed of cells, cells are the basic structural and functional units of life, and all cells arise from pre-existing cells.
• The statement "Cells are the building blocks of living things" directly summarizes the core tenet that cells are the basic structural units of life.
• Other options describe specific characteristics or observation methods but do not summarize the theory itself.

Analyze Question 2

Using the Microscope Magnification knowledge point

• Single-celled organisms (like bacteria and protists) are microscopic and cannot be seen with the naked eye.
• The invention and refinement of the microscope allowed scientists to observe these tiny organisms directly for the first time.
• Other tools listed (thermometer, balance, Petri dish) do not provide the magnification necessary to discover or study individual microscopic cells.

Answer:

Question 1

• (A) Cells are the building blocks of living things. (Correct answer)
• (B) Cells contain a nucleus and other parts.
• (C) Cells can be seen through a microscope.
• (D) Cells come in different shapes and sizes.

Question 2

• (A) the mercury thermometer
• (B) the triple beam balance
• (C) the Petri dish
• (D) the microscope (Correct answer)