Why is haemophilia more common in males than females?

It is X-linked recessive, and males have only one X chromosome

What is the role of restriction enzymes in genetic engineering?

To cut DNA at specific sequences

Populations evolve as advantageous alleles become more common over generations

A geographical barrier that isolates populations

Convert nitrogen gas to ammonia

Active immunity is made by the body and long-lasting; passive is received ready-made and short-lived

12questions. Pick an answer and you'll see why right away.

What is an allele?
Crossing two heterozygous tall pea plants (Tt) gives which expected phenotype ratio?
Why is haemophilia more common in males than females?
What is the role of restriction enzymes in genetic engineering?
In gel electrophoresis, which DNA fragments travel furthest through the gel?
In a population, the frequency of the recessive phenotype (q squared) is 0.16. What is the recessive allele frequency q?
Which statement about natural selection is correct?
What usually causes allopatric speciation?
Roughly what proportion of energy passes from one trophic level to the next?
What do nitrogen-fixing bacteria do in the nitrogen cycle?
Which cells secrete antibodies in the humoral immune response?
What is the difference between active and passive immunity?