Solution idea: Arteries generally carry oxygen-rich blood. About O2, every living thing requires oxygen in order to live. Arteries generally carry blood full of O2.
Q: Arteries generally carry blood full of
Options:
- (A) He
- (B) Au
- (C) O3
- (D) O2
- (E) DDT
- (F) Ni
- (G) CO2
- (H) gas
A: (D)

Solution idea: Viruses are so small that they can be seen only with an electron microscope. Viruses Viruses are very small, a few nanometers in size. Objects that are only a few nanometers in size can be seen only with an electron microscope.
Q: Objects that are a few nanometers in size can be seen only with:
Options:
- (A) an electron microscope
- (B) refraction of light
- (C) matter vibrating
- (D) ultrasound
- (E) The bending of a ray of light
- (F) slight magnification
- (G) flashlights
- (H) lens
A: (A)

Solution idea: Bird beaks are generally adapted for the food they eat. Birds have a beak or a bill. Bird bills are generally adapted for the food they eat.
Q: What part of a bird's body is generally adapted to the kind of food that they eat?
Options:
- (A) bill
- (B) skin
- (C) growth
- (D) sugar
- (E) fat
- (F) H 2 O
- (G) organ
- (H) muscle
A: (A)

Solution idea: Fertilization occurs when a sperm and an egg fuse to form a diploid zygote. Sexual reproduction requires formation of gametes, followed by fertilization. Sexual reproduction involves a sperm and egg fusing to form a diploid zygote.

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Q: What involves a sperm and egg fusing to form a diploid zygote?
Options:
- (A) Leptospirosis
- (B) produce offspring
- (C) allow growth
- (D) sexual reproduction
- (E) metabolic reaction
- (F) peachleaf willow
- (G) rapid expansion
- (H) Plant reproduction
A: (D)