A nymph is 3.0 mm long when it hatches. In a model, its length grows by a factor of 1.2 at every…
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A nymph is long when it hatches. In a model, its length grows by a factor of at every moult. A nymph of this kind moults about times.
- What is the length after the first moult?
- What is the length after moults?
- After which moult does the length first go above ?
Need a reminder? The key ideaShow
The cockroach has separate sexes. The male has a pair of testes, vasa deferentia, a seminal vesicle and an ejaculatory duct. The sperms are packed in bundles called spermatophores. The female has a pair of ovaries, each with eight ovarioles, a genital chamber and a pair of spermathecae. The fertilised eggs are enclosed in capsules called oothecae. A female produces about nine to ten oothecae, each with about fourteen to sixteen eggs. The young nymph resembles the adult and grows by moulting about thirteen times. The earthworm is hermaphrodite with a closed blood system and breathes through its moist skin. The frog has a three-chambered heart, breathes through skin, mouth and lungs, and fertilises its eggs outside the body.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Given. Start . Factor for each moult. The factor is a made up value.
Plan. Multiply by for each moult.
Step 1. One moult. .
Step 2. Thirteen moults. .
Step 3. Over . After moults the length is , which is below . After moults it is .
Answer: ; ; the th moult.
Check. An adult cockroach is about to long, so is of the right size.
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