The answer for this will be C an integration of organ systems this is because the endocrine system also works with the nervous system and immune system etc
Answer: A
Explanation: Its three leafs and tear drop shaped.
The appearance of fossils would the the answer.
Although there has been some scientific debate about what fossil strata should mark the beginning of this period, the "International Geological Congress" determined that the Cambrian period was approximately 543 million years ago of which the first appearance in the fossil record of worms that made horizontal burrows was discovered.
True because carbohydrates are in the cell membrane.
Answer:
In Late 1600s Anton von Leeuwenhoek develops a more powerful microscope that allows him to see living cells like bacteria.
In Early 1800s Matthias Schleiden and Theodor Schwann conclude that all living organisms are made of cells, and that cells can be produced from other cells.
Explanation: