Question

1. practice: consumption and excretion
2. practice: consumption and excretion

respond to the following based on your reading.
question 1
describe the difference between single - loop and double - loop circulatory systems.
check my answer
question 2
what can happen to freshwater animals if they dont have mechanisms that remove water? why does this happen?

Explanation:

Question 1: In single - loop circulatory systems, blood passes through the heart once per circuit, with blood being pumped from the heart to the gills (in fish for example) for oxygenation and then to the rest of the body. In double - loop systems, there are two circuits: the pulmonary circuit (from heart to lungs and back) for oxygenation and the systemic circuit (from heart to the rest of the body and back), and blood passes through the heart twice per complete circuit.
Question 2: If freshwater animals lack water - removal mechanisms, water will continuously enter their bodies by osmosis because the environment is hypotonic relative to their body fluids. This can cause them to swell and potentially burst (lyse) as their cells become over - hydrated.

Answer:

Question 1: In single - loop systems, blood passes through the heart once per circuit, going from heart to gas - exchange organ (e.g., gills) and then to the body. In double - loop systems, there are two circuits (pulmonary and systemic), and blood passes through the heart twice per complete circuit.
Question 2: They can swell and burst. This occurs because the freshwater environment is hypotonic to their body fluids, causing water to enter by osmosis.