HESI A2 Biology Test Latest Update
(25 Questions)
Step-by-step Answer Explanations
PASS GUARANTEE
, 1. 1. Question
Which of the following correctly shows the system of classification from most inclusive to
least inclusive?
Kingdom, Phylum, Class
Phylum, Class, Order
Family, Genus, Species
Order, Family, Genus
Answer:
Kingdom, Phylum, Class
In biology, organisms are classified into groups based on their similarities and evolutionary
relationships. This system is called taxonomy, and it organizes living things into hierarchical
categories from the broadest (most inclusive) to the most specific (least inclusive). The more
inclusive a group, the more different types of organisms it contains. The levels of classification,
from most inclusive to least inclusive, are:
1. Kingdom: This is the broadest category and includes a wide range of organisms.
There are five major kingdoms: Animals, Plants, Fungi, Protists, and Bacteria.
Each kingdom contains a vast number of species with very different
characteristics.
2. Phylum: This category groups organisms based on major structural features. For
example, the Animal Kingdom is divided into various phyla, such as Chordata
(which includes animals with a backbone) and Arthropoda (insects and spiders).
3. Class: Organisms within a phylum are further divided into classes. For example,
within the phylum Chordata, there are classes like Mammalia (mammals) and
Aves (birds).
4. Order: Each class is broken down into orders, which group organisms with more
specific similarities. For example, within the class Mammalia, there are orders
like Carnivora (cats, dogs, and bears) and Primates (humans and monkeys).
, 5. Family: Within each order, organisms are grouped into families, which are even
more closely related. For example, in the order Primates, humans belong to the
family Hominidae.
6. Genus: A genus is a group of closely related species. For example, humans belong
to the genus Homo.
7. Species: This is the most specific level. A species refers to a group of organisms
that can breed and produce fertile offspring. For example, humans belong to the
species Homo sapiens.
The correct order, from most inclusive to least inclusive, is Kingdom, Phylum, Class, Order,
Family, Genus, Species. This classification system allows scientists to organize and study the
diversity of life in a structured way, making it easier to understand relationships between
organisms and their evolutionary history.
2. 2. Question
Which of the following is a characteristic of all living things?
Made of multiple cells
Must move to survive
Capable of photosynthesis
Ability to reproduce
Answer:
Ability to reproduce
One of the key characteristics shared by all living things is the ability to reproduce.
Reproduction ensures the survival and continuation of a species by passing on genetic
information to the next generation. Organisms can reproduce in two main ways:
1. Sexual reproduction: Involves two parents contributing genetic material to
produce offspring that are genetically unique. This process increases genetic
diversity and is common in most animals and plants.
, 2. Asexual reproduction: Involves a single organism producing offspring identical to
itself. This is common in simpler organisms like bacteria, where the organism
divides to create an exact copy of itself.
While multicellular organisms (like humans and animals) are common, not all living things are
made of multiple cells. Many living organisms, such as bacteria, are unicellular—meaning they
consist of only one cell.
Photosynthesis is the process by which certain organisms, like plants and some microorganisms,
convert sunlight into energy. However, this process is not a characteristic of all living things
because many organisms, such as animals, cannot perform photosynthesis.
Finally, movement is not required for all living things. While many animals can move to find
food or escape predators, other living organisms, like plants and stationary bacteria, do not
need to move to survive. Instead, they rely on other mechanisms, like growth or passive
processes, to obtain nutrients and adapt to their environment.
Reproduction is the common trait shared by all living organisms, regardless of their structure or
how they obtain energy. This ability ensures the continuation of life through future generations.
3. 3. Question
Which of the following best describes the polarity of water?
Water molecules have a partial negative charge on the oxygen atom and a partial positive
charge on the hydrogen atoms.
Water molecules have a partial positive charge on the oxygen atom.
Water molecules are nonpolar.
Water molecules have a partial negative charge on the hydrogen atoms.
Answer:
Water molecules have a partial negative charge on the oxygen atom and a partial positive
charge on the hydrogen atoms.
Water is a polar molecule, which means that it has an uneven distribution of electrical charges
across its structure, similar to how a magnet has two opposite poles (north and south). In the
(25 Questions)
Step-by-step Answer Explanations
PASS GUARANTEE
, 1. 1. Question
Which of the following correctly shows the system of classification from most inclusive to
least inclusive?
Kingdom, Phylum, Class
Phylum, Class, Order
Family, Genus, Species
Order, Family, Genus
Answer:
Kingdom, Phylum, Class
In biology, organisms are classified into groups based on their similarities and evolutionary
relationships. This system is called taxonomy, and it organizes living things into hierarchical
categories from the broadest (most inclusive) to the most specific (least inclusive). The more
inclusive a group, the more different types of organisms it contains. The levels of classification,
from most inclusive to least inclusive, are:
1. Kingdom: This is the broadest category and includes a wide range of organisms.
There are five major kingdoms: Animals, Plants, Fungi, Protists, and Bacteria.
Each kingdom contains a vast number of species with very different
characteristics.
2. Phylum: This category groups organisms based on major structural features. For
example, the Animal Kingdom is divided into various phyla, such as Chordata
(which includes animals with a backbone) and Arthropoda (insects and spiders).
3. Class: Organisms within a phylum are further divided into classes. For example,
within the phylum Chordata, there are classes like Mammalia (mammals) and
Aves (birds).
4. Order: Each class is broken down into orders, which group organisms with more
specific similarities. For example, within the class Mammalia, there are orders
like Carnivora (cats, dogs, and bears) and Primates (humans and monkeys).
, 5. Family: Within each order, organisms are grouped into families, which are even
more closely related. For example, in the order Primates, humans belong to the
family Hominidae.
6. Genus: A genus is a group of closely related species. For example, humans belong
to the genus Homo.
7. Species: This is the most specific level. A species refers to a group of organisms
that can breed and produce fertile offspring. For example, humans belong to the
species Homo sapiens.
The correct order, from most inclusive to least inclusive, is Kingdom, Phylum, Class, Order,
Family, Genus, Species. This classification system allows scientists to organize and study the
diversity of life in a structured way, making it easier to understand relationships between
organisms and their evolutionary history.
2. 2. Question
Which of the following is a characteristic of all living things?
Made of multiple cells
Must move to survive
Capable of photosynthesis
Ability to reproduce
Answer:
Ability to reproduce
One of the key characteristics shared by all living things is the ability to reproduce.
Reproduction ensures the survival and continuation of a species by passing on genetic
information to the next generation. Organisms can reproduce in two main ways:
1. Sexual reproduction: Involves two parents contributing genetic material to
produce offspring that are genetically unique. This process increases genetic
diversity and is common in most animals and plants.
, 2. Asexual reproduction: Involves a single organism producing offspring identical to
itself. This is common in simpler organisms like bacteria, where the organism
divides to create an exact copy of itself.
While multicellular organisms (like humans and animals) are common, not all living things are
made of multiple cells. Many living organisms, such as bacteria, are unicellular—meaning they
consist of only one cell.
Photosynthesis is the process by which certain organisms, like plants and some microorganisms,
convert sunlight into energy. However, this process is not a characteristic of all living things
because many organisms, such as animals, cannot perform photosynthesis.
Finally, movement is not required for all living things. While many animals can move to find
food or escape predators, other living organisms, like plants and stationary bacteria, do not
need to move to survive. Instead, they rely on other mechanisms, like growth or passive
processes, to obtain nutrients and adapt to their environment.
Reproduction is the common trait shared by all living organisms, regardless of their structure or
how they obtain energy. This ability ensures the continuation of life through future generations.
3. 3. Question
Which of the following best describes the polarity of water?
Water molecules have a partial negative charge on the oxygen atom and a partial positive
charge on the hydrogen atoms.
Water molecules have a partial positive charge on the oxygen atom.
Water molecules are nonpolar.
Water molecules have a partial negative charge on the hydrogen atoms.
Answer:
Water molecules have a partial negative charge on the oxygen atom and a partial positive
charge on the hydrogen atoms.
Water is a polar molecule, which means that it has an uneven distribution of electrical charges
across its structure, similar to how a magnet has two opposite poles (north and south). In the
