To solve this problem, we need to identify the temporary endocrine gland in the human body from the given options. Let's analyze each option:$\newline \bullet$Option 1: Corpus cardiacum - This is not an endocrine gland in humans. It is found in insects and is involved in hormone release.$\newline \bullet$Option 2: Corpus luteum - This is a temporary endocrine gland in the human body. It forms in the ovary after ovulation and secretes hormones like progesterone, which are crucial for maintaining pregnancy.$\newline \bullet$Option 3: Corpus allatum - This is also not an endocrine gland in humans. It is found in insects and is involved in juvenile hormone production.$\newline \bullet$Option 4: Pineal gland - This is a permanent endocrine gland in the human body, responsible for secreting melatonin.$\newline$Based on the analysis, the correct answer is Option 2: Corpus luteum, as it is the temporary endocrine gland in the human body.