Answer:
Earth formed around 4.54 billion years ago, approximately one-third the age of the universe, by accretion from the solar nebula. Volcanic outgassing probably created the primordial atmosphere and then the ocean, but the early atmosphere contained almost no oxygen.
Explanation:
The actual answer is, "A", an ocean trench.
You can find out more about them by researching them up on Google, it's only a few phrases and a hit on the enter key :P
I'm pretty sure it's primary growth. I might not have studied this type of biology yet, but secondary growth would definitely not be the answer.<span />
The genotype of a normal male zygote is XY, with the X chromosome (sex chromosome) coming from the mother and Y from the father.
Answer: a) substrate and cofactors b) covalent modification
Explanation:
Metabolic pathways involve all the chemical processes takes place in the enviornment or in an organisms.The metabolic pathways are controlled through the catalytic activities of enzymes.
The availability of enzyme is regulated by substrate and cofactors present in enzyme and enzyme activity is commonly regulated via covalent modification.
Enzymes are highly selective in nature and bind to a specific substarte only. The active site in enzyme binds with the substrate to form enzyme substrate complex. Coactors assist the enzyme activity, without cofactor enzyme can not perform its activity.
Hence enzyme availibility is regulated by substrate and cofactors regulates.
Covalent modifications regulates activity of enzyme as it involves addition and removal of chemical group to synthesis required protein. It can change the chemical properties of the site by targeting one or multiple amino acid.
Thus the correct answer is a) substrate and cofactors b) covalent modification
