Once labor begins in childbirth, contractions increase in intensity and frequency until delivery. The increasing labor contractions of childbirth are an example of which type of regulation?

• A bioinformatic system
• Negative feedback
• Positive feedback
• Enzymatic catalysis 

Tags

NGSS.HS-LS1-3

A water sample from a hot thermal vent contained a single-celled organism that had a cell wall but lacked a nucleus. What is its most likely classification?

• Archaea
• Animalia
• Fungi
• Eukarya

Tags

NGSS.MS-LS4-2

In a hypothetical world, every 50 years python snakes over 4 feet long are eliminated from the population before they reproduce. Based on your knowledge of natural selection, you would predict that the average length of the python population will...

• Gradually increase
• Remain unchanged
• Rapidly increase
• Gradually decline

Tags

NGSS.HS-LS4-3

NGSS.HS-LS4-4

What are archaea?

• Bacteria-like organisms that can live only in extreme salt environments.
• Prokaryotes characterized as extremophiles that share some bacterial and some eukaryotic traits.
• Single-celled organisms that are killed by the application of antibiotics at certain concentrations.
• Primitive protist-like creatures possessing fewer than two chromosomes per cell.

A controlled experiment is one in which...

• There are at least two groups, one of which does not receive the experimental treatment.
• The experiment proceeds at a slow pace to guarantee that the scientist can carefully observe all reactions and process all experimental data.
• There is one group for which the scientist controls all variables.
• There are at least two groups, one differing from the other by two or more variables.

Tags

NGSS.MS-PS2-5

Which of the following is a correct sequence of levels in life's hierarchy, proceeding downward from an individual animal?

• Nervous system, brain, nervous tissue, nerve cell
• Organ system, nervous tissue, brain
• Brain, organ system, nerve cell, nervous tissue
• Organ system, tissue, molecule, cell

Tags

NGSS.HS-LS1-2

One difference between carbon-12 and carbon-14 is that carbon-14 has...

• Two more neutrons than carbon–12
• Two more protons and two more neutrons than carbon–12.
• Two more electrons than carbon–12.
• Two more protons than carbon–12.

Tags

NGSS.HS-PS1-8

A covalent bond is likely to be polar when...

• The two atoms sharing electrons are equally electronegative.
• One of the atoms sharing electrons is much more electronegative than the other atom.
• Ooxygen is one of the two atoms sharing electrons.
• One of the atoms has absorbed more energy than the other atom.

Tags

NGSS.HS-PS1-1

How many electron pairs are shared between carbon atoms in a molecule that has the formula C₂H₄?

• 4
• 1
• 0
• 2

Tags

NGSS.HS-PS1-2

Which of the following explains most specifically the attraction of water molecules to one another?

• Ionic bond
• Hydrogen bond
• Hydrophobic interaction
• Polar covalent bond