Carbohydrates are the primary source of energy for living organisms.

Gene cloning is used to produce insulin by inserting the human insulin gene into bacteria, which then produce insulin.

Type O blood is known as the universal donor because it lacks A and B antigens, making it safe for transfusion to any blood type.

The G1 checkpoint assesses the cell's size and DNA integrity before it enters the S phase for replication.

Reptiles are characterized by having scales and typically lay eggs on land.

Reptiles are characterized by the presence of scales, which help in protection and water retention.

Reptiles typically have a three-chambered heart, except for crocodilians which have a four-chambered heart.

Reptiles (Reptilia) are known for having scales and typically lay eggs on land, adapting to terrestrial life.

Class Aves (birds) are warm-blooded, maintaining a constant body temperature.

Class Aves is characterized by the presence of feathers, which are unique to birds.

White blood cells, or leukocytes, are the key players in the immune response, helping to defend the body against infections.

White blood cells (leukocytes) are responsible for the immune response, helping to fight infections and foreign substances.

Blood is a connective tissue that is responsible for the transport of nutrients, gases, and waste products throughout the body.

Adipose tissue stores fat in the body.

Blood is a connective tissue that transports nutrients, gases, and waste products throughout the body.

Tubal ligation is a surgical procedure that permanently prevents pregnancy by blocking the fallopian tubes.

Scurvy is caused by a deficiency of Vitamin C, leading to symptoms like bleeding gums and weakness.

Restriction endonucleases are used to cut DNA at specific sequences, which is essential for DNA cloning.

Restriction endonucleases are used to cut DNA at specific sequences, facilitating gene cloning.

Citrate synthase is an enzyme involved in the Krebs cycle, catalyzing the first step of the cycle.

Pepsin is the enzyme that digests proteins in the acidic environment of the stomach.

Amylase is the enzyme that breaks down carbohydrates into simpler sugars in the mouth.

Helicase is the enzyme that unwinds the DNA double helix during the process of replication.

Trypsin is a pancreatic enzyme that helps in the digestion of proteins in the small intestine.

Trypsin is a proteolytic enzyme secreted by the pancreas that digests proteins in the small intestine.

Oxygen is released as a byproduct of photosynthesis during the light-dependent reactions.

Carbon dioxide levels in the blood primarily drive the urge to breathe; high levels stimulate the respiratory centers in the brain.

Carbon dioxide levels in the blood are the primary factor that regulates the rate of breathing.

Oxygen is released as a byproduct of photosynthesis during the light-dependent reactions.

Carbon dioxide is released as a byproduct during the process of respiration in plants.