The short answer is that cell death by apoptosis in various phases of cell cycle depends on the cell-type and inducer/stimulus. Hematopoietic cells can undergo apoptosis at all stages of cell cycle as noted by Bertrand. However, mesenchymal or epithelial cells usually undergo apoptosis at the G1/S or G2/M phase of the cell cycle.
Skin and Integumentary system protects by forming a selective barrier.
<u>Explanation</u>:
Multicellular organisms unlike unicellular organism have a variety of systems each having a different function. The body of multicellular organisms is covered with epidermis or skin which is known as largest organ of the body. The skin consists of many sensory receptors and protects by enclosing muscles and other body tissues. While Integumentary system is made with skin and its various appendages like hair, feathers, nails etc. with receptors and secretary pores and protects the body from pain.
One answer would be how it would affect the food chain and species that eat that food at a main part of their diet.
