Answer:
Nitrogenous bases have two distinct families known as purines and pyrimidine, nitrogenous are the building blocks or monomer units of the nucleic acids.
The major and significant difference between purines and pyrimidines is the difference in their structures-
The purines are divided into two different bases called adenine and guanine and each of them have a two-ringed structure formed with a 9-membered molecule and 4 nitrogen atoms which makes it a large in size than purines.
The pyrimidines are divided into 3 bases that are cytosine, uracil, and thymine and all these have only one single ring of six members and 2 nitrogen atoms. These are smaller in size.
C is the correct answer they are asymmetrical.
B continue to produce oxygen
Explanation:
carbon will not reduce to synthesise sugars
Answer:
Gel-like fluid present within the cell membrane (excluding nucleus) is termed as cytoplasm of the cell.
It serves various functions in the cell such as:
- It supports and hold all the cell organelles and cell parts.
- It serves as the site of most of the cellular activities or processes.
- It provides shape to the cell.
- It contains the cytoskeleton (actin filaments, intermediate filaments, and microtubules) of the cell which helps in maintaining the cell shape, the movement of materials within the cell, cell division and movement of the cell.
Hence, all options are correct except "determines which substances can enter or leave the cell".
Plasma membrane of the cell determines which substances can enter or leave the cell.
Answer:
( d ) The brittle lithosphere cracks under pressure from the moving asthenosphere.
Explanation:
~ The earth's crust refers to the outer layer of the planet earth . The surface of a planet is usually formed of less dense material than the deeper layers. Only 1/3 of the earth's crust is terrestrial , the rest is covered by oceans . The thickness of the earth's crust is between 10 to 30 miles.
The earth's crust, which is the upper part of the lithosphere , is divided into two layers. The top layer is continental , which is composed of granite . While under granite is a layer of hard rock called basalt .
On a semi-liquid planet , such as Earth , the earth's surface floats on top of the liquid inner layer. The crust seems to be often divided into pieces known as tectonic plates which due to the movement of molten magma beneath it, are able to move. This is a phenomenon of continental drift theory . In addition, collisions between two tectonic plates can produce volcanoes .
The Earth's crust is made up of rocks, minerals, soil and fossil fuels.
