Newest PCA Nematodes Practice Exam with correct answers 2026/2027
version with rationales/instant pdf
1. What are nematodes?
A. Fungi
B. Microscopic, unsegmented roundworms
C. Bacteria
D. Insects
Correct Answer: B. Microscopic, unsegmented roundworms
Rationale: Nematodes are elongated, cylindrical, unsegmented worms found in soil, water,
plants, animals, and other environments.
2. Plant-parasitic nematodes primarily feed on:
A. Plant tissues and cells
B. Rocks
C. Insects only
D. Dead metal
Correct Answer: A. Plant tissues and cells
Rationale: Plant-parasitic nematodes use specialized mouthparts to feed on plant cells.
3. The feeding structure used by many plant-parasitic nematodes is the:
A. Mandible
B. Stylet
C. Proboscis
D. Claw
Correct Answer: B. Stylet
Rationale: The stylet is a needle-like structure used to puncture plant cells and withdraw
nutrients.
4. Which part of a nematode is used to control movement?
A. Muscles
B. Wings
C. Antennae
D. Scales
Correct Answer: A. Muscles
Rationale: Nematodes move using longitudinal muscles working against the fluid-filled body
cavity.
,5. The body of a nematode is generally:
A. Segmented
B. Cylindrical and unsegmented
C. Flat and leaf-like
D. Covered with feathers
Correct Answer: B. Cylindrical and unsegmented
Rationale: Nematodes are commonly characterized by a cylindrical, elongated, unsegmented
body.
6. The outer covering of a nematode is called the:
A. Cuticle
B. Shell
C. Exoskeleton
D. Scale layer
Correct Answer: A. Cuticle
Rationale: The cuticle is the protective outer covering of the nematode.
7. Nematodes increase in size between molts primarily because:
A. The cuticle is shed
B. They grow wings
C. They develop bones
D. They lose their stylet
Correct Answer: A. The cuticle is shed
Rationale: Nematodes molt as they develop through juvenile stages.
8. Most plant-parasitic nematodes are found in:
A. Soil and plant tissues
B. Metal surfaces
C. Dry rocks only
D. Air only
Correct Answer: A. Soil and plant tissues
Rationale: Soil and plant tissues provide food and habitat for many plant-parasitic species.
9. A nematode's stylet is most similar in function to a:
A. Piercing and feeding needle
B. Wing
, C. Foot
D. Gill
Correct Answer: A. Piercing and feeding needle
Rationale: The stylet penetrates plant cells and allows feeding.
10. Plant-parasitic nematodes may damage plants by:
A. Feeding and causing root injury
B. Producing flowers
C. Increasing photosynthesis
D. Improving root growth
Correct Answer: A. Feeding and causing root injury
Rationale: Feeding can destroy root tissues and interfere with water and nutrient uptake.
11. The life cycle of a nematode commonly includes:
A. Egg, juvenile stages, and adult
B. Egg, larva, pupa, and winged adult only
C. Seed and flower only
D. Spore and hypha only
Correct Answer: A. Egg, juvenile stages, and adult
Rationale: Nematodes typically develop through egg, juvenile, and adult stages.
12. The first molt generally occurs:
A. During development from the egg or early juvenile stage
B. Only after adulthood
C. After death
D. Only in plants
Correct Answer: A. During development from the egg or early juvenile stage
Rationale: Juvenile development involves successive molts.
13. Which stage is often especially important in plant infection?
A. Infective juvenile stage
B. Pupa
C. Adult insect
D. Spore
Correct Answer: A. Infective juvenile stage
Rationale: Many species infect plants during specific juvenile stages.
version with rationales/instant pdf
1. What are nematodes?
A. Fungi
B. Microscopic, unsegmented roundworms
C. Bacteria
D. Insects
Correct Answer: B. Microscopic, unsegmented roundworms
Rationale: Nematodes are elongated, cylindrical, unsegmented worms found in soil, water,
plants, animals, and other environments.
2. Plant-parasitic nematodes primarily feed on:
A. Plant tissues and cells
B. Rocks
C. Insects only
D. Dead metal
Correct Answer: A. Plant tissues and cells
Rationale: Plant-parasitic nematodes use specialized mouthparts to feed on plant cells.
3. The feeding structure used by many plant-parasitic nematodes is the:
A. Mandible
B. Stylet
C. Proboscis
D. Claw
Correct Answer: B. Stylet
Rationale: The stylet is a needle-like structure used to puncture plant cells and withdraw
nutrients.
4. Which part of a nematode is used to control movement?
A. Muscles
B. Wings
C. Antennae
D. Scales
Correct Answer: A. Muscles
Rationale: Nematodes move using longitudinal muscles working against the fluid-filled body
cavity.
,5. The body of a nematode is generally:
A. Segmented
B. Cylindrical and unsegmented
C. Flat and leaf-like
D. Covered with feathers
Correct Answer: B. Cylindrical and unsegmented
Rationale: Nematodes are commonly characterized by a cylindrical, elongated, unsegmented
body.
6. The outer covering of a nematode is called the:
A. Cuticle
B. Shell
C. Exoskeleton
D. Scale layer
Correct Answer: A. Cuticle
Rationale: The cuticle is the protective outer covering of the nematode.
7. Nematodes increase in size between molts primarily because:
A. The cuticle is shed
B. They grow wings
C. They develop bones
D. They lose their stylet
Correct Answer: A. The cuticle is shed
Rationale: Nematodes molt as they develop through juvenile stages.
8. Most plant-parasitic nematodes are found in:
A. Soil and plant tissues
B. Metal surfaces
C. Dry rocks only
D. Air only
Correct Answer: A. Soil and plant tissues
Rationale: Soil and plant tissues provide food and habitat for many plant-parasitic species.
9. A nematode's stylet is most similar in function to a:
A. Piercing and feeding needle
B. Wing
, C. Foot
D. Gill
Correct Answer: A. Piercing and feeding needle
Rationale: The stylet penetrates plant cells and allows feeding.
10. Plant-parasitic nematodes may damage plants by:
A. Feeding and causing root injury
B. Producing flowers
C. Increasing photosynthesis
D. Improving root growth
Correct Answer: A. Feeding and causing root injury
Rationale: Feeding can destroy root tissues and interfere with water and nutrient uptake.
11. The life cycle of a nematode commonly includes:
A. Egg, juvenile stages, and adult
B. Egg, larva, pupa, and winged adult only
C. Seed and flower only
D. Spore and hypha only
Correct Answer: A. Egg, juvenile stages, and adult
Rationale: Nematodes typically develop through egg, juvenile, and adult stages.
12. The first molt generally occurs:
A. During development from the egg or early juvenile stage
B. Only after adulthood
C. After death
D. Only in plants
Correct Answer: A. During development from the egg or early juvenile stage
Rationale: Juvenile development involves successive molts.
13. Which stage is often especially important in plant infection?
A. Infective juvenile stage
B. Pupa
C. Adult insect
D. Spore
Correct Answer: A. Infective juvenile stage
Rationale: Many species infect plants during specific juvenile stages.
