The Reason Why Diseases Such as Plague Do Not Kill

question 26

Multiple Choice

The reason why diseases such as plague do not kill as many people today as in the 19ᵗʰ century is

• A)there are now antibiotics which can kill the bacteria responsible for the disease.
• B)the method of transmission is now known so the spread of the disease can be better controlled.
• C)today's standard of hygiene is better.
• D)there are now more vaccines available.
• E)all of the above.

---

Definitions:

Trophoblast

A layer of cells forming the outer shell of a blastocyst, providing nutrients to the embryo and developing into a large part of the placenta.

Extraembryonic Membranes

Membranes that develop outside of the embryo in amniotes, providing protection, nutrition, gas exchange, and waste elimination.

Synapsis

The pairing of two homologous chromosomes that occurs during meiosis, allowing for genetic recombination.

Primary Germ Layers

The three initial layers of cells (ectoderm, mesoderm, and endoderm) in the early embryo from which all bodily tissues and organs develop.