They say how an enzyme perfectly fits into its substrate is alike a "lock and key".
Only one specific enzyme can fit a specific substrate.
white dwarf
Explanation:
A appears on the chart at the point of low luminosity but high surface temperatures. This indicated a White Dwarf
A red giant is highly luminous stars mainly because of its large size. However, its surface temperature is hot a high when compared to white dwarfs. White dwarf surface temperatures can reach billions of degrees kelvin while red giants reach up to 5000 K on their surface.
A white dwarf is the last sequence of a low-mass star cycle and follows the red giant phase.
Known as the cell’s “command center,” the nucleus is a large organelle that stores the cell’s DNA (deoxyribonucleic acid). The nucleus controls all of the cell’s activities, such as growth and metabolism, using the DNA’s genetic information. Within the nucleus is a smaller structure called the nucleolus, which houses the RNA (ribonucleic acid). RNA helps convey the DNA’s orders to the rest of the cell and serves as a template for protein synthesis.
The answer is d) it encloses specific structures