D probably Australian aboriginals were not exposed to these viruses and their body couldn’t fight it off
Answer:
Internal validity.
Explanation:
Internal validity is the study in which trust relationship is build between treatment and outcome. This relationship is known as <em>cause-and-effect. </em>
In this type research, the studies are based on whether the finding is questionable or not. The research which can overrule the possibility of alternative explanations of our findings is internally valid.
The threats of internal valid study are:
- <u>Natural Improvement </u>
- <u>Maturation</u>
- <u>Historical Events</u>
- <u>Placebo effects</u>
- <u>Nonspecific effects</u>.
So, the correct answer is 'Internal validity'.
Explanation:
The can find out by observing the child's behaviour.
So the equation would be 500 km ÷ 10 km/h = 50 (500÷10=50) Therefore your answer is 50