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What is the difference beween biological species concept and the phylogentic approach to defining species?

The biological species concept classifies species as a group of actually or potentially interbreeding individuals. This means that any two individuals (well a male and female) within the group could breed an...
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Answered by Harriet H. • Biology tutor
27232 Views

What is chirality/optical isomerism?

Chirality (or optical isomerism) is a physical property of a molecule which has a non-superimposable mirror image. In other words, a molecule which, when reflected cannot be rotated in any way to make the or...
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Answered by Matthew W. • Chemistry tutor
14070 Views

When do you use the imperfect and when do you use the preterite?

Trying to differentiate between the use of these two tenses can often prove challenging for Spanish students. However, there are some key points that may help you when trying to decide which tense to use. Th...
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Answered by Summer S. • Spanish tutor
4052 Views

How can algebraic expressions be simplified?

In algebra, long expressions can be simplified which makes them easier to solve. We can simplify alebraic expressions by collecting together "like terms". When looking at an expressions such as: 5x...
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Answered by Fraser M. • Maths tutor
12582 Views

What is the difference between "ce" and "se"?

Nothing can distinguishes se and ce when you hear them. However, they have completely different meanings: - you will always find se (or s' ) in front of a verb e.g.: se souvenir -> to remember. It refers ...
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Answered by Domitille S. • French tutor
19757 Views