Oh right thanks i understand the second and third question now. Yeah sorry there was a typo it should be:
1. Which agricultural practice will not provide an alternative to the use of ammonium nitrate as a
fertiliser to increase the productivity of wheat?
A growing wheat and another cereal crop in the same field in alternate years
B growing wheat and beans in the same field in alternate years
C ploughing animal waste such as dung into the soil
D using synthetic urea as a fertiliser
the answer was A. These type of questions come up occasionally in Biology multi-choice questions. I don't really understand how growing wheat and beans in the same field in alternate years provides an alternative source of ammonium nitrate. And i also don't really understand what is the difference between growing wheat and another cereal crop in the same field in alternate years and wheat and another cereal crop in the same field in alternate years. Could someone explain to me why one provides an alternative source of ammonium while the other doesn't? Huh?
Some further Biology questions
.
1. Which enzyme rejoins sections of DNA in genetic engineering?
A DNA ligase
B DNA polymerase
C restriction enzyme
D reverse transcriptase
The answer was A. I was just wondering what happens to DNA polymerase after it links the sugar-phosphate group of the activated nucleotide to the original backbone of the DNA. I'm not exactly sure what DNA ligase is used for and how it rejoins the DNA, could someone explain, Thanks.
2. What is the main effect of heroin on the body?
A It affects metabolic processes in the liver.
B It causes over reaction in muscles.
C It mimics natural neurotransmitters.
D It stimulates reflex pathways through the spinal cord.
The answer was C. I don't think i've covered the effects of heroin in my syllabus. Could someone explain what it means by 'mimics natural neurotransmitters.' thanks a lot.