Top answers

What is the definition of a species?

Scientists have come up with many different definitions of a species over the years; reproductive isolation being key to all concepts. However the most widely accepted is the biological species concept: 'Spe...
AG
Answered by Abigail G. • Biology tutor
5270 Views

What are the events that lead to genetic variation in gametes?

Sources of genetic variation consist of random fertilisation and mutation. Mutation is a product of mistakes made during DNA replication. There are two main types of mutation; point gene mutation and chromos...
DW
Answered by Danielle W. • Biology tutor
18720 Views

What is the difference between unidirectional and multidirectional verbs of motion and when should I use them?

Verbs of motion are one of the most complex aspects of Russian grammar and can be very difficult to get your head around. First and foremost, it is essential to remember that whilst most verbs in Russian com...
NG
Answered by Natasha G. • Russian tutor
13032 Views

How can I prepare for the "unseen poetry" question?

The simple answer to this question is to practice, practice, practice! Find a poetry anthology in your library that you can photocopy, or print out some online poetry (the poetry foundation website has a hug...
VA
4451 Views

How important were the railroads in opening up the American West?

Although other factors contributed greatly the the spread of American civilisation across the Plains, the railroads were incredibly significant for three main reasons: 1. The railways, specifically the Pacif...
CG
Answered by Connor G. • History tutor
15097 Views