Microorganisms, Barriers & Immune Defense — Drills · Grade 7 Science
Chapter: Coordination, Defense & ReproductionWhat these drills covers
By the end of Microorganisms, Barriers & Immune Defense you should be able to:
- I can explain microorganisms, barriers & immune defense.
- I can use evidence, a model, and stated assumptions to support a biological explanation.
4 questions, multiple choice and written answer, each with a worked explanation.
Vocabulary used: microorganism, pathogen, barrier, antibody, immune memory.
Problem 1
Which statement is supported?
- Every bacterium is harmful
- Viruses depend on host cells for replication
- Antibodies are whole organs
- Recognition of A proves universal protection
Answer and explanation
Viruses depend on host cells for replication
Viruses require suitable host-cell processes; bacterial roles and defense outcomes vary.
Problem 2
Why do the supplied symbols not justify a treatment recommendation?
Answer and explanation
They omit real agents, physiology, history, and clinical evidence. They illustrate a recognition concept rather than an actual health decision.
Problem 3
Are all bacteria disease-causing?
Answer and explanation
No. Bacteria have diverse roles, including many that are harmless or beneficial in particular contexts.
Problem 4
Why is a matching-shape model limited?
Answer and explanation
It illustrates recognition but omits molecular complexity, multiple defense pathways, and real organism variation.