Answer:
Luminosity is an intrinsic(natural) measurable property of a star independent of distance. The concept of magnitude, on the other hand, incorporates distance. The apparent magnitude is a measure of the diminishing(decrease) flux of light as a result of distance according to the inverse-square law.
The answer to your question is both C
In humans sperms can survive 3 -5 days within the female reproductive tract.
The ideal time of fertilization is around ovulation when the egg is in the fallopian tube. After travelling through the vaginal canal, the strongest sperm make it to the cervix. From here, the sperm must travel through the uterus and into one of the fallopian tubes.
Multicellular
hope this helps