~Hello there!
Your question: What substance is considered a building block for all living things?
Your answer: Carbon is the substance that is considered s building block for all living things.
Any questions ^?
Happy Studying!
Answer:
accepting electrons at the end of the electron transport chain.
Explanation:
That should be the cell membrane. The cell membrane acts as a filter in and out.
Following gastrulation, the next major development in the embryo is neurulation, which occurs during weeks three and four after fertilization. This is a process in which the embryo develops structures that will eventually become the nervous system