Multiple choice questions on biology: bacteria, biological drawings, characteristics of living things, and control experiments.

Here are the answers to the multiple-choice questions:

1. Choose the most correct answer from the given alternatives and write its letter in the space provided.

• i) _______ are the bacterial caused diseases?

  • A. Tuberculosis, cholera and gonorrhea
  • Explanation: All three diseases (Tuberculosis, Cholera, and Gonorrhea) are caused by bacteria.
  • The correct answer is $\boxed{A}$.

• ii) The magnification of a biological drawing is given as X 0.5. This means that the drawing is:

  • B. Half natural size of the specimen
  • Explanation: A magnification of X 0.5 means the drawing is 0.5 times the actual size, which is equivalent to half the natural size.
  • The correct answer is $\boxed{B}$.

• iii) Mr. Mabala picked up a telephone after hearing it ringing. Which characteristics of living things was Mr. Mabala showing by these actions?

  • B. Irritability and movement
  • Explanation: Hearing the phone ring is a response to a stimulus (irritability), and picking up the phone is a physical action (movement).
  • The correct answer is $\boxed{B}$.

• iv) A teacher was insisting on the use of control experiment when conducting scientific investigation? Why is it useful in conducting scientific investigation?

  • C. Help to build and confirm the conclusion
  • Explanation: A control experiment provides a baseline for comparison, ensuring that any observed changes are due to the variable being tested, thus helping to validate the results and confirm the conclusion.
  • The correct answer is $\boxed{C}$.

• v) Which of the following can be caused by burning plastic waste materials?

  • D. Breathing problems
  • Explanation: Burning plastic releases toxic fumes and particulate matter into the air, which can cause respiratory issues and other health problems when inhaled.
  • The correct answer is $\boxed{D}$.

• vi) The basic importance of all laboratory rules is to;

  • C. Reduce accidents in the laboratory
  • Explanation: Laboratory rules are primarily established to ensure the safety of individuals and prevent accidents.
  • The correct answer is $\boxed{C}$.

• vii) Which one of the following relationships is an example of mutualism?

  • B. Bacterial living in a gut of a cow
  • Explanation: Mutualism is a relationship where both organisms benefit. Bacteria in a cow's gut help digest cellulose, providing nutrients for the cow, while the bacteria get a stable environment and food source.
  • The correct answer is $\boxed{B}$.

• viii) The following waste can be recycled except

  • D. Food remains
  • Explanation: Aluminum cans, plastic bottles, and glass bottles are commonly recycled materials. Food remains are biodegradable and are typically composted or disposed of, rather than industrially recycled in the same manner.
  • The correct answer is $\boxed{D}$.