Answer:
First, the zygote becomes a solid ball of cells. Then it becomes a hollow ball of cells called a blastocyst. Inside the uterus, the blastocyst implants in the wall of the uterus, where it develops into an embryo attached to a placenta and surrounded by fluid-filled membranes.
They may reproduce sexually or asexually through spores.
<h3><u>Answer and Explanation;</u></h3>
- <u>Endosymbiotic theory</u> explains the origin of chloroplasts and mitochondria and their double membrane. Mitochondria of eukaryotes evolved from aerobic bacteria living within their host cell and the chloroplasts of eukaryotes evolved from endosymbiotic cyanobacteria.
- On the other hand according to the <u>autogenous hypothesis, </u>mitochondria and chloroplasts have evolved within the protoeukaryote cell by compartmentalizing plasmids or vesicles of DNA within a pinched off invagination of the cell membrane.
- <u>Endosymbiont theory </u>is the theory that suggests that simple prokaryotic cells were engulfed by larger prokaryotes 1.5 billion years ago.
- <u>Autogenous theory</u> is a theory that was proposed as an alternative to endosymbiont theory. proposes that eukaryotic organelles formed by infolding of the plasma membrane.
- <u>Horizontal gene transfer theory</u> is an alternative to endosymbiont and autogenous theories for the origin of complex organelles in eukaryotes.
Answer:
logging, and oil exploration
Explanation:
The inner layer, the dermis, consists of a superficial papillary region of loose, areolar connective tissue, connective tissue and a thicker and deeper reticular region of dense irregular connective tissue connective tissue.
<h3>The layers of the skin</h3>
The skin is the largest peripheral organ that covers the outer layers of the body. It is made up of two layers namely:
- Epidermis: The epidermis is the outer layer and it is made up of stratified squamous epithelium.
- Dermis: The dermis is the inner layer of skin. it is made up of superficial and deep layers.
The superficial layer is made up of papillary region of loose areolar connective tissue which helps to attach epithelial tissue to other underlying tissues.
While the deep layer is made up of dense irregular connective tissue which provides strength, making the skin resistant to tearing by stretching forces from different directions.
Learn more about the skin here:
brainly.com/question/306377
