Imagine that some change in the environment caused boys to start going into puberty at an earlier age than they ever have in the past. which conclusion is most reasonable?
1. brain development will take place more slowly than it has in the past.
2. self-control and guidance will become even more important than they are today.
3. the situation would be less of a danger with boys than it would be with girls.
4. no specific action would need to be taken.

Match the following terms describing electrical events with the correct phases of the cardiac cycle. the ventricular muscle cells depolarize at the start of this phase. during this phase, na+ entry through the funny channels causes the pacemaker potential of sa nodal cells to gradually become less negative until it reaches threshold. the ventricular muscle cells repolarize right before this phase. the cytosolic concentration of calcium in the contractile cells of the ventricle is highest during this phase. a. isovolumetric relaxation b. ventricular ejection c. isovolumetric contraction d. ventricular filling

Which tool could you see a plant cell? a. a filter b. a microscope c. a microwave d. an electromagnet

What are the characteristics of carbon bonds? check all that apply.