Occurs when a single sperm cell penetrates the ovum.

sodium i think the chemical element of atomic number 11, a soft silver-white reactive metal of the alkali metal group.

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.

instead of copying and pasting things off of tests or work done on computer which im sure you did, try and read over the question carefully