GRADE 9 SCIENCE · CHAPTER 2
Living things & ecosystems
Study each lesson in order, or choose the idea you need today.
- Choose a book
- Choose a chapter
- Study a lesson
Inheritance
Use a simple inheritance model
Use stated allele rules and equally likely model outcomes without generalizing a single-gene model to every trait.
Cells & inheritance
Compare mitosis and meiosis in simplified models
Distinguish the usual chromosome outcomes of mitosis and meiosis in a stated diploid model.
Evolution
Explain natural selection from population evidence
Link heritable variation and differences in reproductive success to changes in a population over generations.
AN EXAMPLE FROM THIS CHAPTER
In an invented plant, A is dominant over a. Which allele pair is heterozygous, meaning two different versions?
Show answer & explanation
Aa
Aa contains two different allele versions.
Curriculum & source notes
These are original Little Play study books organized around U.S. school topics. The official curriculum references below guide topic scope and progression. Coverage is selected, not a complete curriculum or a verified match to every state standard. They are not copies of a publisher’s textbook. Check your school’s syllabus and book edition.
High-school courses can be taken in different years. Choose the topic that matches the student’s current course.
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