Answer:
Internal forces are those forces which exert on each other when the bodies are part of the system. The forces acting between the atoms of molecules that keep them together are example of internal force.
Explanation:
Mature DNA cells do NOT contain DNA.
Answer:
Answer is C. Bacteria
Certain types of bacteria have a relationship with certain plants where they help convert nitrogen into a usable form.
Explanation:
Nitrogen is abundant in the atmosphere, but plants cannot use it because of the absence of a necessary enzyme, nitrogenase, which converts nitrogen into a usable form. So they form a symbiotic relationship (mutually-beneficial arrangement) with nitrogen fixing soil bacteria (rhizobia) which perform biological nitrogen fixation. Biological nitrogen fixation is a process in which the symbiotic nitrogen-fixing bacteria coverts atmospheric nitrogen into ammonia and organic derivatives that plants can use to synthesize proteins. This bacteria form nodules on the roots of plants like legumes in which nitrogen fixation takes place.
Both plants and bacteria benefit from this symbiotic relationship, as the plant obtains ammonia to synthesize proteins from nitrogen in the atmosphere while bacteria obtain carbon compounds from the plant produced through photosynthesis and a secure environment to grow. As the plant roots leave behind some of the usable form of nitrogen in the soil, this process also increase soil fertility.
The right answer is B. Chromosome
In its most scientifically rigorous definition, a chromosome is a fully condensed structure of chromatin.
In optical microscopy, condensed regions formed of heterochromatin and decondensed regions of euchromatin are distinguished on the chromosomes. The genes expressed are located mainly at the level of euchromatin.
