The placenta forms at 8 weeks, and develop for 6 weeks. hope this helps
Answer:
Yes, All of the cells divide at approximately the same rate, although they may divide at different times
Answer:
Patterns can occur within one species of organism or across many species. Students who understand the concepts can: Use graphs, charts, and images to identify patterns within the fossil record. Analyze and interpret data within the fossil record to determine similarities and differences in findings.
Explanation:
Answer:
Explanation:
The main function of the plasma membrane is to protect the cell from its surroundings. Made of a phospholipid bilayer with embedded proteins, the plasma membrane is selectively permeable to ions and organic molecules it also regulates the movement of substances in and out of cells. Plasma membranes must be very flexible in order to allow certain cells, such as red blood cells and white blood cells, to change shape as they pass through narrow capillaries. Membrane receptors provide extracellular attachment sites for effectors like hormones and growth factors, which then trigger intracellular responses. Some viruses, such as Human Immunodeficiency Virus (HIV), can intercept these receptors to get into the cells, causing infections.
