Answer:
Humus
Explanation:
Also known as the uppermost layer of soil, that's for making soil more fertile due to its organic content.
Answer:
Cell membrane as a semi permeable membrane.
Explanation
A semi permeable membrane is the one that would only allow water,ions and certain molecules to pass through it by diffusion while restricting other large molecules from passing through.
Details in the attachment.
Adaptions to collect and retain water - thick, non-pourous stems, not leaves, but thick lobes and the ability to store water until its needed.
Answer:
its the spinal cord and the brain
