I believe the biggest space mission of the twenty-first century will be a manned mission to Mars, and the colonization that follows. This is the stated goal of several nations, companies, and individuals, all with considerably deep pockets. This mission will not only be a huge leap forward in space exploration, it will usher in a new era in human history in which the human race is an interplanetary civilization, a natural milestone as humanity continues to progress and advance.
Significant challenges are many and overwhelming. In terms of getting to mars, we need efficient, powerful propulsion systems and a spaceship that can not only accommodate a full crew for a mission that would likely last years, but withstand the various hazards that a long trip through space and entrance into the Martian atmosphere will entail. In terms of colonization, significant challenges will include establishing efficient and frequent travel/transport between the planets, and in the longer term, the necessity to terraform the planet (make it more like Earth) so that humans can more easily live there.
Answer:
1) c. five
2) a. lysine and arginine
3) g. two
4) d. four
Explanation:
A nucleotide can be defined as an organic molecule which forms the building block of nucleic acid such as deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
Basically, nucleotide comprises of the following parts;
1. Nitrogenous base: this includes adenine (A), thymine (T), guanine (G), and cytosine (C) which are mainly found in the DNA while adenine (A), guanine (G), uracil (U) and cytosine (C) are found in the RNA.
2. A phosphate group.
3. A penrose sugar: it is either deoxyribose in DNA or ribose in RNA.
The two parts or chemical components of a nucleotide which do not change throughout the structure of DNA are;
I. Five-Carbon Sugar also known as deoxyribose and it has hydrogen on its second carbon.
II. Phosphate: this is the structural backbone that provides support to DNA.
Histones are a group of highly basic proteins that are mainly associated with deoxyribonucleic acid (DNA) in the nucleus of a living organism and then condense it to chromatin.
Histones include five main classes of relatively small basic proteins containing relatively large amounts of lysine and arginine. Nucleosomes are made of two each of four types of histones.
First answer is , as the work of ventricle is to push blood to he whole body , so it has to be strong or it can not pump blood to head to the toe !
as in frog (an amphibian ) it has only three chambers as two artia and one ventricle, so the oxygenated blood from left artia and deoxygenated blood from right , combines and thus partial oxygenated blood is circulated !
Answer and explanation
Due to technical problems, you will find the complete answer and explanation in the attached files
