The autonomic nervous system regulates involuntary bodily functions such as heart rate and digestion.

The blood-brain barrier protects the brain from harmful substances while allowing essential nutrients to pass through.

The cell membrane regulates the transport of substances in and out of the cell.

Cilia in the respiratory tract help to clear debris and pathogens by moving mucus upwards towards the throat.

The corpus luteum primarily produces progesterone, which is essential for maintaining the uterine lining during early pregnancy.

The cytoskeleton provides structural support, helps maintain cell shape, and is involved in cell movement.

The epiglottis is a flap that covers the trachea during swallowing, preventing food and liquid from entering the airway.

The Golgi apparatus modifies, sorts, and packages proteins for secretion or use within the cell.

Oxytocin is involved in childbirth by stimulating uterine contractions and is also associated with social bonding.

The immune system protects the body against infections and diseases by identifying and destroying pathogens.

The kidneys filter blood to remove waste and excess substances.

Lysosomes contain enzymes that break down waste materials and cellular debris.

The nucleus serves as the control center of the cell, housing the cell's genetic material.

The pancreas produces digestive enzymes that help in the digestion of carbohydrates, proteins, and fats.

The petals of a flower are often brightly colored and serve to attract pollinators such as bees and butterflies.

The preposition 'through' shows the place where the action occurs.

The respiratory system is responsible for the exchange of gases, primarily oxygen and carbon dioxide, in the body.

The rough endoplasmic reticulum is studded with ribosomes and is primarily involved in the synthesis of proteins.

Selectable marker genes are used to identify cells that have successfully taken up the recombinant DNA, allowing researchers to select for those cells.

The seminal vesicles produce a fluid that provides nutrients to sperm and helps form semen.

Sepals protect the flower bud before it opens.

The skeletal system provides structure and protection for internal organs, making option 2 the correct answer.

The stigma is the part of the flower that receives pollen during pollination, allowing fertilization to occur.

The style is the slender stalk that connects the stigma to the ovary, allowing pollen to travel to the ovules.

The synaptic cleft is the small gap between two neurons where neurotransmitters are released to facilitate communication.

Taq polymerase is a heat-stable enzyme used in PCR to synthesize new DNA strands by extending primers during the amplification process.

Villi increase the surface area of the small intestine, enhancing nutrient absorption.

Xylem is responsible for the transport of water and minerals from the roots to the rest of the plant.

Villi increase the surface area of the small intestine, enhancing the absorption of nutrients.

The functional group of alcohols is the hydroxyl group (-OH).