Changes that occur during an experiment, a scientist makes a(n)_____.
a. variable
b. control
c.hypothesis
d. conclusion

When human cells are first attacked by a virus, the cells may produce_____.
a. a vaccine
b. interferon
c. an antibody
d. an antibiotic

Villi are located in the ___.
a. small intestine
b. large intestine
c. epiglottie

A single nerve cell is called a ____.
a. brain
b. neuron
c. spinal cord
d. nephron

Evidence that life existed in the past is called a ____.
a. mutation
b. fossil
c. variation
d. selection

At the end of an experiment, a scperiment, a scientist makes a(n)____.
a. hypothesis
b. observation
c. problem
d. conclusion

To determine whether a disease is caused by a certain bacterium, scientists use ____.
a. antiseptics
b. antibiotics
c. Koch's postulates
d. vaccines

Which organ helps with the digestion of fat, protein, and carbohydrate?
a. salivary glands
b. pancreas
c. liver
d. large intestine

Blood pressure and heartbeat are controlled by your brain's ___.
a. cerebrum
b. cerebellum
c. lobes
d. medulla

A trait that is inherited on sex chromosomes is ____.
a. eye color
b. dyslexia
c. cystic fibrosis
d. hemophilia

A liter is used to measure ___.
a. length
b. volume
c. mass
d. weight

The complex worms are the _______.
a. flatworms
b. roundworms
c. segmented worms
d. hookworms

The right side of the heart pumps blood only to the ____.
a. lungs
b. body
c. brain
d. liver

A reflex may or may not use the ____.
a. spinal cord
b. skin's neurons
c. brain
d. body's muscles

Animals that are most fit for their surrondings usually ____.
a. are killed
b. survive
c. do not reproduce
d. kill other animals

A group of similar cells carrying out a specific job is a(n) ______.
a. organ
b. tissue
c. organ system
d. organism

There are more kinds of ____ than all other animals combine.
a. insects
b. millipedes
c. spiders
d. scorpions

The ____ prevents food from entering the trachea.
a. bronchus
b. nasal chamber
c. diaphragm
d. epiglottis

Taste buds detect____.
a. sounds
b. molecules
c. pressures
d. colors

If both parents are color-blind, the chance of their children being color-blind is ____.
a. 1/4
b. 2/4
c. 3/4
d. 4/4

Living things get energy from food in the process of ___.
a. osmosis
b. diffusion
c. photosynthesis
d. cellular respiration

Hookworms are parasitic____.
a. segmented worms
b. roundworms
c. flatworms
d. leeches

As you breathe in, the diaphragm will be ____.
a. relaxed
b. contracted
c. pushing up
d. unable to work

Concaine is dangerous because it can speed up and then stop ____.
a. muscle action
b. withdrawal
c. heartbeat
d. behavior

DNA controls the ____ of living things
a. number
b. traits
c. behavior
d. environment