Depends which elements are listed.
However, I will tell you that the first shell can only be occupied by a maximum of two electrons and the rest after that can have a maximum of 8 :)
Answer:
Digestive
Explanation:
The by-products of digestion are solid waste which is removed through egestion.
Sensory neurons
Process
Light falls onto retina. The retina generates an impulse that is carried to the brain by the sensory neurons. An impulse is not carried by blood vessels, so that crosses out A. A muscle cant carry impulses either. Spinal cord isnt the answer because it doesnt have to go through the spine because the eye and brain is so close together
DNA is composed of nucleotides, which are composed of three parts:
1. A five carbon carbohydrate (pentose)
Pentose is classified as a monosaccharide (simple carbohydrate), and its molecular formula is represented by
. They are water soluble molecules with sweet taste. Monosaccharides may have from three carbon atoms (trioses) to six (hexoses). In DNA is present pentose (5 carbon atoms)
2. A nitrogenous base
Nitrogenous bases are ring-shaped compounds that contain nitrogen in their molecular structure. They are classified into two groups: purines and pyrimidines
The purine bases are adenine (A) and guanine (G). They are larger and contain more than one ring in their structure,.
The pyrimidines, cytosine (C), uracil (U) and thymine (T), are smaller and composed of a single ring.
3. One or more phosphate groups
A phosphate consists of a trivalent anion that contains one phosphorus atom and four oxygen atoms. Its molecular formula is expressed by
.