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If the concentration of testosterone in a man’s blood starts to rise above normal, this system leads to a reduction in testosterone. How does this occur?

Students are aware of the Hyothalamus-pituitary axis (HPA axis) in the female, but are not as aware about the role of the HPA axis in the male reproductive system. Here,we should start off by explaining t...

Answered by Thahesh T. • Biology tutor

3463 Views

How is the process by which plants turn towards a light source called and what is the role of auxin (IAA) in it?

The process is called phototropism (‘photo’-light, ‘tropism’ – ‘tendency of an animal or plant to turn or move in response to a stimulus’). IAA (Indole Acetic Acid) is a plant hormone belonging to a class...

Answered by Emiliya T. • Biology tutor

7219 Views

Name a substance that can be transported across a membrane by simple diffusion and explain why it is able to be transported by this method.

Oxygen is an example of a molecule that is able to move across a membrane via simple diffusion. It is able to do so as it is a non-polar, uncharged molecule. Thus, it is a lipophillic molecule which means...

Answered by Tamarind R. • Biology tutor

2176 Views

How do I write a good introduction for essays?

A good introduction is very important for an essay. It conceptualises the essay and shows the examiner you understand not only the words in the question, but what the question is asking of you. A good int...

Answered by Stephanie K. • History tutor

2091 Views

How do I know which verbs take 'etre' and which verbs take 'avoir' in the past tense?

The best to learn which verbs take 'etre' is through MS VANDERTRAMP. (Then I would explain what each letter stands for). After this I would remind the student of compound verbs. For example, entrer is a v...

Answered by Gemma M. • French tutor

3245 Views