How does a focal length change as a convex lens becomes flatter?

How does a focal length change as a convex lens becomes flatter? what does a beetle eat?how long does it live? How many sides does a house have? how many sides does a house has? how many sides does a houes have How many sides does a circle have? how many sides does a snowflake have how many legs does a spider have how many legs does a spider have how long does a pupa last how many sides does a decagon How many wheels does a jeep have? How many (foot) does a monkey have? How does a table tennis player how fast does a dalloon travel? How fast does a balloon travel? 英语作文：How does a plant grow? how many wings does a butterfly have?