Answer:
Primary source is more reliable, but writers tend to use both primary and secondary source.
Answer:telescopes
Explanation:person that's doing it i think
The answer is Eukaryote that is the sea spiders' domain
Answer: a. testing effect
Explanation:
Testing effect is a type of threat to internal validity of an experiment. Internal validity is assessing whether a factor makes a difference in an experiment or not and if it does, whether there is adequate evidence to support this correlation.
Testing as a threat to internal validity is when a second test is taken on the outcome of a first test. Other internal validity threats are history, maturation, instrument modifications.