Answer:
1.75 billion years
Explanation:
Scientists have concluded that Earth could potentially continue to host life for at LEAST another 1.75 billion years. As long as there's no natural disasters or nuclear wars, we should be good. (Right?)
But, eventually, over time Earth will become uninhabitable. :o
Germ layer is a primary layer of cells found in the embryo. The three primary germ layers that generate most of the cells in the developing mammalian forelimb are ectoderm, mesoderm and endoderm.
Ectoderm forms the outer component of a mammalian body such as skin, hair, etc. Endoderm forms the inner layer that comprises of the linings of digestive system, lungs and thyroid. Mesoderm is the middle layer that forms the skeletal system, heart, etc.
Neural tube is generated by the inward folding of the ectoderm. This process is called neurulation. Ectoderm also forms neural crest.
Answer:
Dehydration reaction is the chemical reaction that links the MONOMERS together by removing a HYDROGEN ATOM form one monomer and an OH GROUP from a second molecule creating a COVALENT BOND between these molecules. The H ATOM and the OH GROUP will be bonded as well to form a water molecule. On the other hand, HYDROLYSIS is a chemical reaction that BREAK down POLYMERS introducing a water molecule and breaking the covalent between the monomers in the polymers.
Explanation:
Carbohydrates, proteins and nucleic acids are polymers of simpler sugars, amino acids and nucleotides respectively. Monomer molecules are joined together to form a polymer by dehydration reactions and a water molecule is released. On the other hand, hydrolytic reactions break down polymers into monomers by adding water molecules to them.
For example, a dehydration reaction joins two amino acids together by a peptide bond (a specific type of covalent bond that joins the amino acids) to form a dipeptide. During the reaction, one amino acid loses an H atom and the other loses its OH group to release a water molecule.
Breakdown of proteins into amino acid occurs by hydrolytic reactions in which water molecules are added to amino acids to breakdown the peptide bonds between them.
