TEXAS RS STUDY GUIDE 300 PRACTICE QUESTIONS
WITH ANSWERS AND RATIONALES 2026/2027
EDITION
---
SECTION 1: ENVIRONMENTAL HEALTH & GENERAL SCIENCE (Questions 1-50)
1. Muerto Canyon virus (MCV) is a Hantavirus mainly carried by:
A) Rats
B) Mice
C) Squirrels
D) Rabbits
Answer: B – Mice
Rationale: Muerto Canyon virus is a Hantavirus primarily carried by deer mice.
Hantaviruses are transmitted to humans through contact with rodent urine,
droppings, or saliva, making rodent control essential for prevention .
2. The wastewater from the flushing of a water closet, latrine, or privy is referred
to as:
A) Grey water
B) Black water
C) Combined sewage
,D) Storm water
Answer: B – Black water
Rationale: Black water specifically refers to wastewater containing human waste
from toilets, latrines, and privies. This is distinct from grey water, which comes
from sinks, showers, and washing machines without fecal contamination .
3. Bloodborne pathogens are regulated by:
A) EPA
B) OSHA
C) FDA
D) CDC
Answer: B – OSHA
Rationale: The Occupational Safety and Health Administration (OSHA) regulates
bloodborne pathogens through the Bloodborne Pathogens Standard (29 CFR
1910.1030). This standard mandates exposure control plans, universal
precautions, and training for workers at risk of occupational exposure .
4. Excessive condensation, corrosion, and mildew occur when the relative
humidity exceeds:
A) 40%
B) 50%
C) 60%
D) 70%
,Answer: C – 60%
Rationale: When relative humidity exceeds 60%, conditions become favorable for
mold growth, corrosion, and condensation problems. Maintaining indoor humidity
between 30-50% is recommended to prevent these issues and control dust mites .
5. The maximum size of a stair riser should be:
A) 7"
B) 7 ¾"
C) 8 ¼"
D) 9"
Answer: C – 8 ¼"
Rationale: Building codes typically limit stair riser height to 8 ¼ inches maximum
to ensure safe and comfortable stair climbing. This dimension, along with
minimum tread depth requirements, helps prevent falls and accidents .
6. Low acid foods have a pH between:
A) 2.0 – 3.6
B) 3.7 – 4.5
C) 4.6 – 7.0
D) 7.1 – 9.0
Answer: C – 4.6 – 7.0
, Rationale: Low acid foods have a pH above 4.6, with the range of 4.6 to 7.0 being
critical for food safety. These foods require more stringent processing (like
pressure canning) because pathogenic bacteria, particularly Clostridium
botulinum, can grow at pH levels above 4.6 .
7. Which of the following is MOST effective for controlling ragweed?
A) Glyphosate
B) 2,4-D
C) Atrazine
D) DDT
Answer: B – 2,4-D
Rationale: 2,4-D (2,4-dichlorophenoxyacetic acid) is a selective herbicide widely
used for controlling broadleaf weeds like ragweed. It is effective against this
common allergen-producing plant while generally leaving grasses unharmed .
8. A joist is used as a:
A) Vertical support
B) Horizontal support
C) Diagonal bracing
D) Foundation footing
Answer: B – Horizontal support
WITH ANSWERS AND RATIONALES 2026/2027
EDITION
---
SECTION 1: ENVIRONMENTAL HEALTH & GENERAL SCIENCE (Questions 1-50)
1. Muerto Canyon virus (MCV) is a Hantavirus mainly carried by:
A) Rats
B) Mice
C) Squirrels
D) Rabbits
Answer: B – Mice
Rationale: Muerto Canyon virus is a Hantavirus primarily carried by deer mice.
Hantaviruses are transmitted to humans through contact with rodent urine,
droppings, or saliva, making rodent control essential for prevention .
2. The wastewater from the flushing of a water closet, latrine, or privy is referred
to as:
A) Grey water
B) Black water
C) Combined sewage
,D) Storm water
Answer: B – Black water
Rationale: Black water specifically refers to wastewater containing human waste
from toilets, latrines, and privies. This is distinct from grey water, which comes
from sinks, showers, and washing machines without fecal contamination .
3. Bloodborne pathogens are regulated by:
A) EPA
B) OSHA
C) FDA
D) CDC
Answer: B – OSHA
Rationale: The Occupational Safety and Health Administration (OSHA) regulates
bloodborne pathogens through the Bloodborne Pathogens Standard (29 CFR
1910.1030). This standard mandates exposure control plans, universal
precautions, and training for workers at risk of occupational exposure .
4. Excessive condensation, corrosion, and mildew occur when the relative
humidity exceeds:
A) 40%
B) 50%
C) 60%
D) 70%
,Answer: C – 60%
Rationale: When relative humidity exceeds 60%, conditions become favorable for
mold growth, corrosion, and condensation problems. Maintaining indoor humidity
between 30-50% is recommended to prevent these issues and control dust mites .
5. The maximum size of a stair riser should be:
A) 7"
B) 7 ¾"
C) 8 ¼"
D) 9"
Answer: C – 8 ¼"
Rationale: Building codes typically limit stair riser height to 8 ¼ inches maximum
to ensure safe and comfortable stair climbing. This dimension, along with
minimum tread depth requirements, helps prevent falls and accidents .
6. Low acid foods have a pH between:
A) 2.0 – 3.6
B) 3.7 – 4.5
C) 4.6 – 7.0
D) 7.1 – 9.0
Answer: C – 4.6 – 7.0
, Rationale: Low acid foods have a pH above 4.6, with the range of 4.6 to 7.0 being
critical for food safety. These foods require more stringent processing (like
pressure canning) because pathogenic bacteria, particularly Clostridium
botulinum, can grow at pH levels above 4.6 .
7. Which of the following is MOST effective for controlling ragweed?
A) Glyphosate
B) 2,4-D
C) Atrazine
D) DDT
Answer: B – 2,4-D
Rationale: 2,4-D (2,4-dichlorophenoxyacetic acid) is a selective herbicide widely
used for controlling broadleaf weeds like ragweed. It is effective against this
common allergen-producing plant while generally leaving grasses unharmed .
8. A joist is used as a:
A) Vertical support
B) Horizontal support
C) Diagonal bracing
D) Foundation footing
Answer: B – Horizontal support
