Questions

Electrons are stripped from water in the light reactions of photosynthesis. Light provides the energy to excite electrons.

ATP and NADPH are both products of the light reactions and are used to power the Calvin cycle.

The halogens make up group 17 in the periodic table.

They are five elements:

Chlorine (Cl)

Fluorine (F)

Bromine (B)

Iodine (I)

Astatine (At).

But astatine is not purely halogen as it is radioactive.

Amino acids are organic compounds containing amine (-NH2) and carboxyl (-COOH) functional groups, along with a side chain (R group) specific to each amino acid.

Depending on the nature of the side chain groups, three classes of aminoacids can e distinguished:

1. Amino acids with H ond donor and acceptor groups.

Histidine, lysine, aspartic acid, threonine,...

2. Amino acids with donor grups only.

Arginine, tryptophan and cysteine.

3. Amino acids with acceptor groups only.

Asparagine and glutamine.

In all plants and animal cells chromosomes are located in the Nucleus of the cells.

The Chromosomes are thread like structures present in the nucleus of the cells which are made up of proteins and a single molecule of DNA.

Their function is to carry the characteristic features of parent cells to daughter cells. 

The shortest gestation period known is 12 to 13 days, shared by three marsupials: the American or Virginian opossum (Didelphis marsupialis); the rare water opossum, or yapok (Chironectes minimus) of central and northern South America; and the eastern native cat (Dasyurus viverrinus) of Australia.

Gestation is the period of time between fertilization and birth in oviparous animals.

The elephant has the longest gestation period of about 23 months of any land animal.