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Question 19M.1A.SL.TZ1.29

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Date May 2019 Marks available [Maximum mark: 1] Reference code 19M.1A.SL.TZ1.29
Level SL Paper 1A Time zone TZ1
Command term Identify Question number 29 Adapted from N/A
29.
[Maximum mark: 1]
19M.1A.SL.TZ1.29

The diagram shows a graph of an action potential.

[Source: https://www.ncbi.nlm.nih.gov/books/NBK538143/figure/article-17127.image.f1/?report=objectonly
Physiology, Action Potential by Michael H. Grider and Carolyn S. Glaubensklee.
Copyright © 2019, StatPearls Publishing LLC
https://creativecommons.org/licenses/by/4.0/]

 

What is happening at X?

A. Sodium channels close.

B. Calcium channels open.

C. Sodium channels open.

D. Potassium channels close.

[1]

Markscheme

A

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