What is the difference between cross-sectional and longitudinal research?
a: one method is qualitative research and the other is an experiment.
b: each study requires a different amount of time involved.
c: one research method studies people and the other method studies animals.
d: no difference really exists between the two.

I think the answer is either B or C, hope this helps! Sorry if it doesn't!

By using internet

1. true.2. true.3. true.4. false.5. true.the concept of darwin's theory of evolution involves the idea that there are limited resources in a given living environment and that the organisms which live within have variations in their genetic make up due to random mating. the ones with beneficial genetic variations can express certain traits which give them an upper hand in surviving and reproducing in the said environment compared to ones who may have a more disadvantageous variation in traits. over time, the organisms with an upper hand will survive and reproduce more frequently and pass on their beneficial genes while the others die. the result is evolution, where we observe (usually, but not always) eventually, phenotypic distinct changes.