Question

the following question has two parts. first, answer part a. then, answer part b.
part a
a student places a marine plant in fresh water.
which answer describes a response of the cells in the plant stem?

• the cells will expand.
• photosynthesis will stop.
• waste products will increase.
• cellular respiration will slow down.

part b
select all of the features of the plant cell that protect it when placed in the solution.

• the rigid cell wall slows the rupturing of the cell
• the nucleus signals organelles to begin removing salt.
• mitochondria produce more energy to expel water.
• the vacuole provides a location for storage of excess water.
• the cell membrane restricts the movement of water into or out of the cell

Explanation:

Part A

Step1: Recall Osmosis in Plant Cells

Plant cells have a cell wall and a large vacuole. When a marine plant (adapted to salt water, hypertonic) is placed in fresh water (hypotonic), water moves into the cell via osmosis.

Step2: Analyze Each Option

• "The cells will expand": Since water enters the cell, the cell (and vacuole) will expand. The cell wall will prevent bursting but allow expansion.
• "Photosynthesis will stop": Fresh water doesn't stop photosynthesis; light, CO₂, etc., are still available.
• "Waste products will increase": No direct relation to fresh water exposure increasing waste.
• "Cellular respiration will slow down": Fresh water doesn't inhibit respiration; energy production needs remain.

Step1: Analyze Each Feature

• "The rigid cell wall slows the rupturing of the cell": Cell wall provides structural support, so when water enters, it slows bursting (rupturing) as it resists excessive expansion. Correct.
• "The nucleus signals organelles to begin removing salt": Marine plant in fresh water has less salt outside, no need to remove salt; nucleus doesn't signal this. Incorrect.
• "Mitochondria produce more energy to expel water": Water enters via osmosis (passive), no energy needed to expel; mitochondria don't produce energy for this. Incorrect.
• "The vacuole provides a location for storage of excess water": Vacuole can store excess water entering the cell. Correct.
• "The cell membrane restricts the movement of water into or out of the cell": Cell membrane is semi - permeable, but in osmosis, water moves freely (facilitated by aquaporins). It doesn't restrict water movement in this context to prevent entry; it allows osmosis. Incorrect.

Answer:

The cells will expand.

Part B