What goes up but never ever comes down?

answer:

dank memes

Explanation: let me elaborate... the memes will always stay on the internet. and even if they die. they wont be deleted... therefore they go up on the interent. but never come down. or are erased fully in memory

answer:

age

Explanation:

Age works because we are always growing older, but we are not growing younger

a tetrad is the foursome during meiosis made by two homologous chromosomes that have each already replicated into a pair of sister chromatids.

the correct answer is: b. pantala flavescens, because these organisms would have a high level of genetic variation due to sexual reproduction.  

because involves two organisms (parents) whose genetic material combines, sexual reproduction leads to genetic variation in new generations of offspring. the offspring is an unique organism, with new genome, more protected with the higher ability to adapted. this process is fundamental to evolution.