Question 1

Which of the following best explains how the theory of evolution unifies all life on Earth?

Accepted Answer

It shows that all living organisms share a common ancestor and have diversified through natural selection.

Question 2

Which of the following is NOT one of the three main points of Darwin’s Theory of Evolution?

Accepted Answer

All species are unrelated and evolve independently.

Question 3

A population of finches on the Galápagos Islands develops different beak shapes over generations. Which process best explains this phenomenon?

Accepted Answer

Natural selection acting on heritable variation in beak shape.

Question 4

Which statement best describes the unity and diversity of life on Earth?

Accepted Answer

All living things share a common set of chemical building blocks but have evolved diverse forms and functions.

Question 5

Which of the following is the correct definition of a compound?

Accepted Answer

A substance consisting of two or more different elements combined in a fixed ratio.

Question 6

Which four elements make up about 96% of living matter?

Accepted Answer

Carbon, hydrogen, oxygen, and nitrogen

Question 7

What is the difference between an essential element and a trace element?

Accepted Answer

Essential elements are required in large amounts, while trace elements are needed in minute quantities for proper biological function.

Question 8

Which subatomic particle is directly involved in chemical reactions between atoms?

Accepted Answer

Electron

Question 9

Given the periodic table entry for nitrogen ($\mathrm{N}$): atomic number 7, atomic mass 14.01, how many protons, neutrons, and electrons does a neutral nitrogen atom have?

Accepted Answer

7 protons, 7 neutrons, 7 electrons

Question 10

Which of the following best describes an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons

Question 11

Radioactive isotopes are used in science for which of the following purposes?

Accepted Answer

Dating fossils and tracing biochemical pathways

Question 12

Which formula correctly calculates the number of neutrons in an atom?

Accepted Answer

$	ext{Number of neutrons} = 	ext{atomic mass} - 	ext{atomic number}$

Question 13

How many valence electrons does a carbon atom have?

Accepted Answer

4

Question 14

Which of the following atoms is most likely to form three covalent bonds to fill its outer shell?

Accepted Answer

Nitrogen ($\mathrm{N}$)

Question 15

Which statement about valence electrons is correct?

Accepted Answer

Valence electrons are found in the outermost shell and determine an atom’s chemical reactivity.

Question 16

A helium atom has an atomic number of 2 and an atomic mass of 4. How many neutrons does it have?

Accepted Answer

2

Question 17

Which of the following best describes the atomic nucleus?

Accepted Answer

It contains protons and neutrons and is positively charged.

Question 18

Which of the following is a real-world example of natural selection?

Accepted Answer

Antibiotic resistance in bacteria due to survival of resistant strains.

Question 19

Which of the following best explains why atomic masses on the periodic table are not whole numbers?

Accepted Answer

They represent the weighted average of all naturally occurring isotopes of the element.

Question 20

Which of the following is the correct electron configuration for a nitrogen atom ($\mathrm{N}$, atomic number 7)?

Accepted Answer

$1s^2\ 2s^2\ 2p^3$

Lecture 3

Study Guide - Practice Questions

Study Guide - Flashcards