The correct option is (c) 1 and 3 only
Explanation
Algae are chlorophyll-bearing, simple, thalloid, autotrophic, and largely aquatic (both fresh water and marine) organisms. They are capable of performing photosynthesis, which defines their mode of nutrition and pigmentation.
Statement-wise Analysis
- Statement 1 is Correct: Algae are commonly observed as slimy, green patches in stagnant water bodies or on wet surfaces. Their growth is often accelerated in nutrient-rich stagnant water, leading to phenomena such as algal blooms.
- Statement 2 is Incorrect: Algae appear green specifically because they contain chlorophyll. Chlorophyll is the green pigment essential for photosynthesis. If they lacked chlorophyll, they would not appear green nor be able to perform photosynthesis efficiently.
- Statement 3 is Correct: Algae are autotrophs. Due to the presence of chlorophyll, they capture sunlight to synthesize their own food through the process of photosynthesis, similar to higher plants.
Key Takeaway: Algae are photosynthetic autotrophs that contain chlorophyll, which gives them their characteristic green color and enables them to synthesize their own food.