Answer:
A purine always forms a complementary base pair with a pyrimidine.
Explanation:
Purine bases such as Adenine pair specifically with Thymine , a pyrimidine base forming two bonds; just as Guanine pair specifically with Cytosine forming three bonds.
This specific base pairing are complimentary in nature and grants stability to the DNA.
Answer:
These specialized cells and parts of the immune system offer the body protection against disease. This protection is called immunity. Humans have three types of immunity — innate, adaptive, and passive: Innate immunity: Everyone is born with innate (or natural) immunity, a type of general protection.
Explanation:
Energy is usually related to the metabolic processes of living organisms in its organic form.
Many cellular processes require a steady supply of energy provided by the cell’s metabolism. Signaling molecules such as hormones and neurotransmitters must be synthesized and then transported between cells. Pathogenic bacteria and viruses are ingested and broken down by cells. Cells must also export waste and toxins to stay healthy, and many cells must swim or move surrounding materials via the beating motion of cellular appendages like cilia and flagella.
