During a visit to a desert ecosystem, a student observes the following:
• A hawk eats a snake.
• A lizard eats a fly.
• A tortoise eats small patches of grass.
• A snake eats a mouse.
Based on student's observations of how each of these organisms
obtain's energy, which of the following statements is the best
conclusion?
A. The hawk is a primary consumer.
B. The grass and the desert tortoise are both primary
consumers.
C. The lizard is a tertiary consumer.
D. The lizard and the snake are secondary consumers

D. The lizard and the snake are secondary consumers .

Explanation;

Option A is not correct because the hawk is a secondary consumer.

Option B is not correct because the grass is not a primary consumer.

Option C is not correct because the lizard is a secondary consumer.

This leaves us with option D: the snake is a secondary consumer (it eats the mouse) and the lizard is a secondary consumer (it eats the fly). This, option D is the correct answer.

Double helix is the description of the structure of a DNA molecule. A DNA molecule consists of two strands that wind around each other like a twisted ladder.