D. Man-Made is the answer
Serial Monogamy is the behavior n mating in which one male breeds with a female for a certain period of time and then finds a different mate the following mating season. It is defined as a succession of short monogamous relationships or <span>the practice of having a number of long-term romantic or sexual partners in succession.</span>
The body structure ( ovaries, testes, and external genitalia) that make sexual reproduction possible. Secondary spermatocytes
The answer is microscopic life appeared on Earth before flowering plants. This is because according to the label on the second box, microscopic life appeared 4.0 to 3.5 billion years ago, and this is way before the date 250 to 120 millions years ago indicated on the label on the sixth box the flowering plants appeared on Earth.