The fluid that surrounds the brain and spinal cord is: MCQ with Answer and Explanation

Explanation:
Gymnosperms are seed-producing plants where the ovules are not enclosed in an ovary; hence, the seeds are naked. They are predominantly perennial, evergreen, woody trees like pines and cedars. Double fertilization and the formation of triploid endosperm are unique characteristics of angiosperms, not gymnosperms. Thus, statements 1 and 2 are correct.

Explanation:
The sarcoplasmic reticulum is a specialized smooth endoplasmic reticulum in muscle cells that stores and releases calcium ions, which trigger muscle contraction. Mitochondria produce ATP, Golgi processes proteins, nucleus controls gene expression.

Explanation:
Molecular cloning involves inserting a DNA fragment into a vector (e.g., plasmid), which is then taken up by host cells (e.g., E. coli). As the bacteria replicate, they produce many copies of the inserted DNA, creating a gene library. PCR amplifies without vectors, sequencing reads bases, microarrays analyze expression.