Cindy is studying cognitive development during adulthood. She administers several memory and problem-solving tasks to a group of 20-year-olds, a group of 40-year-olds, and a group of 70-year-olds. Cindy is using a research design.

1. cross-sequential
2. cross-sectional
3. simultaneous
4. longitudinal

2. Cross- Sectional

Step-by-step explanation:

Cross-sectional research involves using different groups of people who differ in the variable of interest but share other characteristics, such as socioeconomic status, educational background, and ethnicity.

Cross sectional design research design involves looking at a data from a population at one specific point in time. Cross-sectional studies are used to describe what is happening at the present moment. Analysis of cross sectional data usually consists of comparing the differences among selected subjects.

45

step-by-step explanation:

to find a percentage, add a decimal in front and multiply it by the other number.

.25 times 180= 45