Answer the following question given this paragraph: Each silicon atom has four valence electrons it shares with other silicon atoms in a crystal. A semiconductor is formed by replacing a few silicon atoms with other atoms that have more or less valence electrons than silicon. Q: Each silicon atom shares how many valence electrons with other silicon atoms in a crystal? Choices: - five - ten - three - four A:
four
Answer the following question given this paragraph: Elongation is the addition of nucleotides to the mRNA strand. Q: Elongation is the addition of what to the mrna strand? Choices: - codons - glycine - filaments - nucleotides A:
nucleotides
Q: Answer the following question given this paragraph: The first horizon is the "A" horizon. It is more commonly called the topsoil . The topsoil is usually the darkest layer of the soil. It is the layer with the most organic material. Humus forms from all the plant and animal debris that falls to or grows on the ground. The topsoil is also the region with the most biological activity. Many organisms live within this layer. Plant roots stretch down into this layer. The roots help to hold the topsoil in place. Topsoil is needed to grow most crops ( Figure below ). Q: What is the "a" horizon commonly known as? Choices: - sediment - core - crust - topsoil A:
A: topsoil
Question: Answer the following question given this paragraph: Q: How do organophostbate pesticides work? Choices: - inhibiting reticulum - inhibiting cryptosporidium - inhibiting testosterone - inhibiting acetylcholinesterase A:
Answer: inhibiting acetylcholinesterase
*Question*
Answer the following question given this paragraph: The amount of kinetic energy in a moving object depends directly on its mass and velocity. An object with greater mass or greater velocity has more kinetic energy. You can calculate the kinetic energy of a moving object with this equation:. Q: The amount of kinetic energy in a moving object depends directly on its mass and what else? Choices: - volume - direction - density - velocity A:
**Answer**
velocity
Answer the following question given this paragraph: Within seconds of birth, the umbilical cord is cut. Without this connection to the placenta, the baby can't exchange gases, so carbon dioxide quickly builds up in the baby's blood. This stimulates the baby's brain to trigger breathing, and the newborn takes her first breath. Q: What structure connects the fetus to the placenta, allowing the exchange of gases? Choices: - sediment cord - skin cord - belly button - umbilical cord A:
umbilical cord