Answer:
they are smaller then cells
Explanation:
they are composed of many atoms
<h3><u>Answer;</u></h3>
A. Gas exchanges takes place by diffusion.
B. It is an open system.
<h3><u>Explanation</u>;</h3>
- Most molluscs and arthropods have an open type of circulatory system.
- Open circulatory systems pump blood into a hemocoel with the blood diffusing back to the circulatory system between cells.
- Blood is pumped by a heart into the body cavities, where tissues are surrounded by the blood.
Answer:
Pia mater
Explanation:
Three meninges cover the brain and spinal cord. Pia mater refers to the deepest meninx of the brain. It is a thin delicate layer of connective tissue. It is a transparent connective tissue layer like that of cellophane. Being a transparent and thin tissue layer, it looks like a cellophane wrap adhered to the surface of the brain.
Oceanic crust is constantly formed at mid-ocean ridges, where tectonic plates are tearing apart from each other. As magma that wells up from these rifts in Earth's surface cools, it becomes young oceanic crust. ... Just as oceanic crust is formed at mid-ocean ridges, it is destroyed in subduction zones.
