Final answer:
Proteins are important for the cell because they have multiple functions including maintaining cell shape, muscle tissues, transportation, chemical reactions, and fluid balance. The function of the nuclear membrane is to separate and protect the nucleus.
Step-by-step explanation:
Proteins are important for the cell because they have multiple functions. They help cells maintain their shape, make up muscle tissues, transport substances in and out of cells, act as signals, and speed up chemical reactions in cells. They also play a role in maintaining fluid balance and electrolyte balance in and out of the cell. Therefore, the correct answer is d. All of the above.
The function of the nuclear membrane is to separate the nucleus internal parts and protect the nucleus internal parts. Therefore, the correct answer is c. Both a and b.