Thin filaments are composed of three proteins. which one is the longest?
a. myosin
b. tropomyocin
c. troponin

b. tropomyocin

Explanation:

The thin filament is made up of three proteins mainly. These are actin, troponin, and tropomyosin.  

Among these three proteins of the thin filament, actin and troponin are globular proteins. The globular proteins have a spherical shape and are shorter in length.  

On the other hand, tropomyosin is a rod-shaped protein. Each molecule of tropomyosin has around 284 amino acids. The protein is helix in nature and has a filamentous structure. Hence, among the three proteins of the thin filament, tropomyosin is the longest one. One molecule of tropomyosin can cover the seven molecules of actin proteins.  

9.9 years

a = p(1 + rt) . . account balance after time t at rate r starting with principal p

3000 = 2500(1 + 0.0202t) . . filling in the given numbers

1.2 = 1 + 0.0202t . . divide by 2500

0.2 = 0.0202t . . . subtract 1

0.2/0.0202 = t ≈ 9.901

it will take about 9.9 years for the account balance to reach $3000.