Key terms & definitions

A ridge of glacial debris deposited during a pause in the retreat of a glacier's snout.

The speed at which an object is moving away from an observer.

Describes an allele that is expressed in the phenotype only when two copies are present and no dominant allele is present.

An allele expressed in the phenotype only when two copies are present and no dominant allele is present, in the simple inheritance model.

An allele that is expressed in the phenotype only when two copies are present and no dominant allele is present.

An allele expressed in the phenotype only when two copies are present.

The replenishment of groundwater as water soaks into the ground.

A battery whose chemical energy store can be restored using an external electrical supply, allowing repeated use.

A cell whose chemical reactions can be reversed by supplying an external electrical current, allowing the cell to be used again.

A cell that can have its chemical energy store restored by supplying electrical energy from a suitable charger.

A change to a recipe’s ingredients, quantities, preparation or cooking method to make it more suitable for a particular need.

Calculating the cost of the quantities of ingredients used in a recipe and adding them together.

A change to a recipe's ingredients, quantities or preparation to suit particular needs or circumstances.

A country or community that receives aid.

The number obtained by dividing 1 by a non-zero value; the reciprocal of $x$ is $\frac{1}{x}$.

A responsibility that is matched by a responsibility from the other person: for example, parents care for children, and children support their parents.

A function involving division by the variable; the required basic reciprocal function is $y=\frac{1}{x}$, where $$.

A graph involving the reciprocal $\frac{1}{x}$; for $y=\frac{1}{x}$, each non-zero is paired with divided by .

Love or affection that is shared and returned by both people.

A relationship of the form $y=\frac{k}{x}$, where $$ is constant and ; equivalently, .

Repeated back-and-forth movement along a straight line.

Repeated back-and-forth movement along a straight line.

Repeated back-and-forth movement along a straight line.

A relationship in which affection, trust or support is given and received by both people.

The principle that responsibilities and care operate in both directions: each person gives support as well as receiving it.

Wood recovered from an earlier use so that it can be used again rather than discarded.

Wastewater that has been treated so that it can be reused.

The recovery or reform of someone who has gone wrong. The Ghost uses this word to describe its purpose in helping Scrooge change.

A moment when a character discovers someone’s true identity or recognises a previously hidden relationship.

Identifying something as having been encountered before, such as selecting a previously shown colour from several alternatives.