Hello please help i’ll give brainliest

Where do homologous chromosomes exchange genetic material through crossing over?               a.  chlorophyll    b.  centrosomes    c.  centromeres    d.  chiasma

Which best explains why there are 64 possible codons in the genetic code and only 20 amino acids that make protiens of living organisms on earth

Which statement describes an endocrine function rather than an exocrine function? a. salivary glands release saliva into the mouth. b. sweat glands release sweat onto the skin c. the pineal gland releases melatonin into the blood. d. esophageal glands release mucus into the esophagus.