# Tutor profile: Caitlin S.

## Questions

### Subject: Basic Math

3x - 2 = 10

Step 1) Add 2 to both sides of the equation Step 2) Divide each side of the equation by 3 Step 3) Solve x = 4

### Subject: Basic Chemistry

The hospital where you work has just received a 40-g sample of chromium-1. Chromium-51 is used for measuring a patient's blood volume. Your patient has just made an appointment for 4 weeks from now. How much of the sample will have decayed in 4 weeks?

Step 1) The half-life of chromium-51 is 27.8 days. Step 2) Therefore, after 4 weeks, half of the sample will have decayed. Step 3) 40g/2 = 20g Half of the sample will have decayed in 4 weeks, leaving 20g of the sample remaining.

### Subject: Biology

A flock of birds with various beak sizes migrates to a new island in the Pacific ocean where their customary food is not available. However, there are plants on the island that produce a variety of large nuts, which can be eaten by birds with the largest beaks. There are also plants that produce a variety of small, soft seeds, which can be eaten by birds with the smallest beaks. Over time, this population divides into two species with large and small beaks. This is an example of

Disruptive Selection

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