Sea squirts are invertebrates that are close relatives of vertebrates. Which similarities woul support this claim? A. Embryonic stages B. Dietary habits C. Ecological niches D. Chromosome numbers

## Step 1<br />The problem is asking us to identify the similarities between sea squirts (also known as tunicates) and vertebrates that would support the claim that sea squirts are close relatives of vertebrates. The options provided are embryonic stages, dietary habits, ecological niches, and chromosome numbers.<br /><br />## Step 2<br />The first option, embryonic stages, refers to the developmental stages of an organism from fertilization to birth. If sea squirts and vertebrates share similar embryonic stages, it would suggest a common ancestry and thus support the claim that they are close relatives.<br /><br />## Step 3<br />The second option, dietary habits, refers to the types of food that an organism eats. While sea squirts and vertebrates may share similar dietary habits, this does not necessarily indicate a close evolutionary relationship. Many organisms can have similar dietary habits but be unrelated.<br /><br />## Step 4<br />The third option, ecological niches, refers to the role and position an organism has in its environment. While sea squirts and vertebrates may share similar ecological niches, this also does not necessarily indicate a close evolutionary relationship. Many organisms can occupy similar ecological niches but be unrelated.<br /><br />## Step 5<br />The fourth option, chromosome numbers, refers to the number of chromosomes in an organism's cells. While sea squirts and vertebrates may share similar chromosome numbers, this also does not necessarily indicate a close evolutionary relationship. Many organisms can have similar chromosome numbers but be unrelated.<br /><br />## Step 6<br />Based on the above analysis, the most likely answer is A, embryonic stages. This is because shared embryonic stages are a strong indicator of common ancestry and thus would support the claim that sea squirts are close relatives of vertebrates.